Semiconductor integrated circuit apparatus and electronic apparatus

ABSTRACT

Semiconductor integrated circuit apparatus and electronic apparatus having a leakage current detection circuit where arbitrarily set leakage current detection ratio does not depend on power supply voltage, temperature, or manufacturing variations, and where leakage current detection is straightforward. Semiconductor integrated circuit apparatus extracts a stable potential from the center of two NchMIS transistors, amplifies drain current of an NchMOS transistor taking this potential as a gate potential to a current value of an arbitrary ratio using current mirror circuit, makes this current value flow through NchMOS transistor with the gate and drain connected, and applies drain potential of this NchMOS transistor to the gate of leakage current detection NchMOS transistor.

CROSS REFERENCE RELATED TO APPLICATION

This is a continuation of pending U.S. application Ser. No. 12/482,044,filed on Jun. 10, 2009, which is divisional of U.S. application Ser. No.11/549,209, filed Oct. 13, 2006, now U.S. Pat. No. 7,564,296, whichissued on Jul. 21, 2009, which claims priority to Japanese ApplicationNos. 2005-299209, filed Oct. 13, 2005 and 2006-175899, filed Jun. 26,2006, the contents of which are expressly incorporated herein byreference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor integrated circuitapparatus that controls threshold voltage of MIS (Metal InsulatedSemiconductor) transistor, and particularly relates to a semiconductorintegrated circuit apparatus and electronic apparatus capable ofcontrolling substrate voltage of fine-detailed MIS transistors operatingat low power supply voltages.

2. Description of the Related Art

In recent years, methods of lowering power supply voltage are well-knownas important methods for making semiconductor integrated circuits low inpower consumption. However, by lowering the power supply voltage,fluctuations in threshold voltages of MIS transistors or MOS (MetalOxide Semiconductor) transistors have a substantial influence onoperating speed of semiconductor integrated circuits.

With regards to this problem, in the related art, circuit technology formaking variations in threshold voltage small has been developed. Forexample, the operation described below is carried out using a leakagecurrent detection circuit and substrate voltage circuit incorporated ina semiconductor integrated circuit. Namely, when the threshold voltageis lower than a target value, leakage current increases to more than atarget value and the detected leakage current therefore becomes largerthan a set value. As a result, the substrate voltage circuit operatesand makes the substrate voltage lower, and the threshold voltage iscorrected to be higher. Conversely, when the threshold voltage is higherthan a target value, leakage current falls to less than a target valueand the detected leakage current therefore becomes smaller than a setvalue. As a result, the substrate voltage circuit makes the substratevoltage higher, and the threshold voltage is corrected to be lower. Forexample, see Document 1, Kobayashi, T. and Sakurai, T., “Self-AdjustingThreshold-Voltage Scheme (SATS) for Low-Voltage High-Speed Operation.”Proc. IEEE 1994 CICC, pp. 271-274, May 1994.

Further, as shown in FIG. 23, as a circuit configuration for a leakagecurrent detection circuit, two NchMOS transistors M_(1n) and M_(2n) withgates both connected to a first current supply M_(gp) are connected inseries, and drain potential V_(bn) of M_(1n) is applied to the gate ofleakage current detection NchMOS transistor M_(Ln). The two NchMOStransistors M_(1n) and M_(2n) are then made to operate in thesub-threshold region so as to generate input potential V_(bn) of leakagecurrent detection NchMOS transistor M_(Ln). Leakage current detectionratio therefore does not depend on power supply voltage or temperature(see, Document 2: Japanese Patent Application Laid-Open No.HEI9-130232).

However, semiconductor integrated circuit apparatus of the related arthas the following three problems.

First, leakage current detected by leakage current detection NchMOStransistor M_(Ln) is extremely small, in the order of a few pA to a fewtens of pA. It is therefore extremely difficult to implement a constantcurrent source where a minute stable current flows due to the influenceof microscopic leakage currents due to defects in the processes of anMOS transistor and increases in the size of MOS transistors etc. Inaddition, the response to the substrate voltage control operation delaysdue to the delayed change in the drain potential of the leakage currentdetection NchMOS transistor M_(Ln). This results in fluctuation insubstrate voltage which presents a first problem.

A second problem is that, in Document 1 and Document 2, the leakagecurrent detection circuit is always operating and is therefore alwaysconsuming power.

Further, in recent years, the operating speed of the power supplyvoltage changes according to the operating speed which presents a thirdproblem that how the threshold voltage is to be set for a changingsystem clock frequency and power supply voltage appropriately has been abig problem.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide asemiconductor integrated circuit apparatus and an electronic apparatushaving a leakage current detection circuit where an arbitrarily setleakage current detection ratio does not depend on power supply voltage,temperature or manufacturing variations, and where detection of leakagecurrent is straightforward and response to substrate voltage control isfast.

According to an aspect of the present invention, a semiconductorintegrated circuit apparatus comprises a reference potential generatingcircuit, a current mirror circuit that amplifies or attenuates draincurrent of an MIS transistor taking an output potential of the referencepotential generating circuit as a gate potential to a current value ofan arbitrary ratio, and a leakage current detection circuit constitutedby an MIS transistor that takes output potential of the current mirrorcircuit as a gate potential.

According to a further aspect of the present invention, a semiconductorintegrated circuit apparatus comprises a reference potential generatingcircuit, a voltage amplifying circuit that amplifies or attenuates anoutput potential of the reference potential generating circuit to apotential of an arbitrary ratio, and a leakage current detection circuitconstituted by an MIS transistor that takes a potential amplified by thevoltage amplifying circuit as a gate potential.

According to another aspect of the present invention, a semiconductorintegrated circuit apparatus comprises a first first main conductivityMIS transistor with a source connected to a first power supply, a secondfirst main conductivity MIS transistor with a source connected to adrain of the first first main conductivity MIS transistor, a drainconnected to a first current source, and a gate connected to a gate ofthe first first main conductivity MIS transistor and the first currentsource, and a current mirror circuit that amplifies or attenuates draincurrent of a third first main conductivity MIS transistor with a sourceconnected to the first power supply, and that takes a drain potential ofthe first first main conductivity MIS transistor as a gate potential, toa current value of an arbitrary ratio. Here, the first and second firstmain conductivity MIS transistors operate in a sub-threshold region insuch a manner that an absolute value of a difference in gate potentialof the first first main conductivity MIS transistor and the second firstmain conductivity MIS transistor and the first power supply potentialbecomes equal to or smaller than a threshold voltage of the first andsecond first main conductivity MIS transistors.

According to a still further aspect of the present invention, asemiconductor integrated circuit apparatus comprises a first first mainconductivity MIS transistor with a source connected to a first powersupply, a second first main conductivity MIS transistor with a sourceconnected to a drain of the first first main conductivity MIStransistor, a drain connected to a first current source, and a gateconnected to a gate of the first first main conductivity MIS transistorand the first current source, and a voltage amplifying circuit thatamplifies or attenuates drain potential of the first first mainconductivity MIS transistor to a potential of an arbitrary ratio. Thefirst and second first main conductivity MIS transistors operate in asub-threshold region in such a manner that an absolute value of adifference in gate potential of the first first main conductivity MIStransistor and the second first main conductivity MIS transistor and thefirst power supply potential becomes equal to or smaller than athreshold voltage of the first and second first main conductivity MIStransistors.

According to another aspect of the present invention, a semiconductorintegrated circuit apparatus comprises a first first main conductivityMIS transistor with a source connected to a first power supply, a secondfirst main conductivity MIS transistor with a source connected to adrain of the first first main conductivity MIS transistor and a drainconnected to a first current source, a fourth first main conductivityMIS transistor with a source connected to the first power supply, a gateand drain connected in common and connected to respective gates of thefirst first main conductivity MIS transistor and the second first mainconductivity MIS transistor and a second current source, and a currentmirror circuit that amplifies or attenuates drain current of a thirdfirst main conductivity MIS transistor with a source connected to thefirst power supply, and that takes a drain potential of the first firstmain conductivity MIS transistor as a gate potential, to a current valueof an arbitrary ratio. The first, second and fourth first mainconductivity MIS transistors operate in a sub-threshold region in such amanner that an absolute value of a difference in gate potential of thefirst first main conductivity MIS transistor, the second first mainconductivity MIS transistor, and the fourth first main conductivity MIStransistor becomes equal to or smaller than a threshold voltage of thefirst, second, and fourth first main conductivity MIS transistors.

According to a further aspect of the present invention, a semiconductorintegrated circuit apparatus comprises a first first main conductivityMIS transistor with a source connected to a first power supply, a secondfirst main conductivity MIS transistor with a source connected to adrain of the first first main conductivity MIS transistor and a drainconnected to a first current source, a fourth first main conductivityMIS transistor with a source connected to the first power supply, a gateand drain connected in common and connected to respective gates of thefirst first main conductivity MIS transistor and the second first mainconductivity MIS transistor and a second current source, and a voltageamplifying circuit that amplifies or attenuates drain potential of thefirst first main conductivity MIS transistor to a potential of anarbitrary ratio. The first, second and fourth first main conductivityMIS transistors operate in a sub-threshold region in such a manner thatan absolute value of a difference in gate potential of the first firstmain conductivity MIS transistor, the second first main conductivity MIStransistor, and the fourth first main conductivity MIS transistorbecomes equal to or smaller than a threshold voltage of the first,second, and fourth first main conductivity MIS transistors.

According to another aspect of the present invention, a semiconductorintegrated circuit apparatus comprises an internal circuit having aplurality of MIS transistors on a semiconductor substrate, a substratevoltage control block that supplies a substrate voltage to the internalcircuit and controls threshold voltage for the MIS transistors of theinternal circuit, a reference potential generating circuit, a currentmirror circuit that amplifies or attenuates drain current of an MIStransistor taking an output potential of the reference potentialgenerating circuit as a gate potential to a current value of anarbitrary ratio, and a leakage current detection circuit constituted byan MIS transistor with the substrate voltage supplied by the substratevoltage control block, and that takes output potential of the currentmirror circuit as a gate potential. Here, the threshold voltage iscontrolled by inputting an output signal of the leakage currentdetection circuit to the substrate voltage control block.

According to a further aspect of the present invention, a semiconductorintegrated circuit apparatus comprises an internal circuit having aplurality of MIS transistors on a semiconductor substrate, a substratevoltage control block that supplies a substrate voltage to the internalcircuit and controls threshold voltage for the MIS transistors of theinternal circuit, a reference potential generating circuit, a voltageamplifying circuit that amplifies or attenuates an output potential ofthe reference potential generating circuit to a potential of anarbitrary ratio, and a leakage current detection circuit constituted byan MIS transistor with the substrate voltage supplied by the substratevoltage control block, and that takes a potential amplified orattenuated by the voltage amplifying circuit as a gate potential. Here,the threshold voltage is controlled by inputting an output signal of theleakage current detection circuit to the substrate voltage controlblock.

According to a still further aspect of the present invention, asemiconductor integrated circuit apparatus comprises an internal circuithaving a plurality of MIS transistors on a semiconductor substrate, asubstrate voltage control block that supplies a substrate voltage to theinternal circuit and controls threshold voltage for a first mainconductivity MIS transistor of the internal circuit, a referencepotential generating circuit composed of a first first main conductivityMIS transistor with a source connected to a first power supply, and asecond first main conductivity MIS transistor with a source connected toa drain of the first first main conductivity MIS transistor, a drainconnected to a first current source, and a gate connected to a gate ofthe first first main conductivity MIS transistor and the first currentsource, and that generates a stable reference potential from the drainof the first first main conductivity MIS transistor, a current mirrorcircuit that amplifies or attenuates drain current of a third first mainconductivity MIS transistor with a source connected to the first powersupply, and that takes the reference potential as a gate potential to acurrent value of an arbitrary ratio, a fifth first main conductivity MIStransistor with a gate and drain connected, and a current valueamplified by the current mirror circuit flowing through, and a leakagecurrent detection first main conductivity MIS transistor with a sourceconnected to the first power supply, a drain connected to the thirdcurrent source, and a drain potential of the fifth first mainconductivity MIS transistor applied to a gate, and substrate voltagecontrolled by the substrate voltage control block. The first and secondfirst main conductivity MIS transistors operate in a sub-thresholdregion in such a manner that an absolute value of a difference in gatepotential of the first first main conductivity MIS transistor and thesecond first main conductivity MIS transistor and the first power supplypotential becomes equal to or smaller than a threshold voltage of thefirst and second first main conductivity MIS transistors, and thethreshold voltage is controlled by inputting a signal based onfluctuation in drain potential of the leakage current detection firstmain conductivity MIS transistor to the substrate voltage control block.

According to another aspect of the present invention, a semiconductorintegrated circuit apparatus comprises an internal circuit having aplurality of MIS transistors on a semiconductor substrate, a substratevoltage control block that supplies a substrate voltage to the internalcircuit and controls threshold voltage for a first main conductivity MIStransistor of the internal circuit, a reference potential generatingcircuit composed of a first first main conductivity MIS transistor witha source connected to a first power supply, and a second first mainconductivity MIS transistor with a source connected to a drain of thefirst first main conductivity MIS transistor, a drain connected to afirst current source, and a gate connected to a gate of the first firstmain conductivity MIS transistor and the first current source, and thatgenerates a stable reference potential from the drain of the first firstmain conductivity MIS transistor, a voltage amplifying circuit thatamplifies or attenuates the reference potential to a potential of anarbitrary ratio, a leakage current detection first main conductivity MIStransistor with a source connected to the first power supply, a drainconnected to a third current source, a potential amplified by thevoltage amplifying circuit applied to a gate, and substrate voltage iscontrolled by the substrate voltage control block. Here, the first andsecond first main conductivity MIS transistors operate in asub-threshold region in such a manner that an absolute value of adifference in gate potential of the first first main conductivity MIStransistor and the second first main conductivity MIS transistor and thefirst power supply potential becomes equal to or smaller than athreshold voltage of the first and second first main conductivity MIStransistors, and the threshold voltage is controlled by inputting asignal based on fluctuation in drain potential of the leakage currentdetection first main conductivity MIS transistor to the substratevoltage control block.

According to a further aspect of the present invention, a semiconductorintegrated circuit apparatus comprises an internal circuit having aplurality of MIS transistors on a semiconductor substrate, a substratevoltage control block that supplies a substrate voltage to the internalcircuit and controls threshold voltage for a first main conductivity MIStransistor of the internal circuit, a reference potential generatingcircuit composed of a first first main conductivity MIS transistor witha source connected to a first power supply, a second first mainconductivity MIS transistor with a source connected to a drain of thefirst first main conductivity MIS transistor and a drain connected to afirst current source, and a fourth first main conductivity MIStransistor with a source connected to the first power supply, a gate anddrain in common and connected to the respective gates of the first firstmain conductivity MIS transistor and the second first main conductivityMIS transistor and a second current source, that generates a stablereference potential from the drain of the first first main conductivityMIS transistor, a current mirror circuit that amplifies or attenuatesdrain current of a third first main conductivity MIS transistor with asource connected to the first power supply, and that takes the referencepotential as a gate potential to a current value of an arbitrary ratio,a fifth first main conductivity MIS transistor with a gate and drainconnected, and a current value amplified by the current mirror circuitflowing through, and a leakage current detection first main conductivityMIS transistor with a source connected to the first power supply, adrain connected to a third current source, a drain potential of thefifth first main conductivity MIS transistor applied to a gate, andsubstrate voltage controlled by the substrate voltage control block. Thefirst, second and fourth first main conductivity MIS transistors operatein a sub-threshold region in such a manner that an absolute value of adifference in gate potential of the first first main conductivity MIStransistor, the second first main conductivity MIS transistor, and thefourth first main conductivity MIS transistor becomes equal to orsmaller than a threshold voltage of the first, second, and fourth firstmain conductivity MIS transistors, and the threshold voltage iscontrolled by inputting a signal based on fluctuation in drain potentialof the leakage current detection first main conductivity MIS transistorto the substrate voltage control block.

According to a still further aspect of the present invention, asemiconductor integrated circuit apparatus comprises an internal circuithaving a plurality of MIS transistors on a semiconductor substrate, asubstrate voltage control block that supplies a substrate voltage to theinternal circuit and controls threshold voltage for a first mainconductivity MIS transistor of the internal circuit, a referencepotential generating circuit composed of a first first main conductivityMIS transistor with a source connected to a first power supply, a secondfirst main conductivity MIS transistor with a source connected to adrain of the first first main conductivity MIS transistor and a drainconnected to a first current source, and a fourth first mainconductivity MIS transistor with a source connected to the first powersupply, a gate and drain in common and connected to the respective gatesof the first first main conductivity MIS transistor and the second firstmain conductivity MIS transistor and a second current source, and thatgenerates a stable reference potential from the drain of the first firstmain conductivity MIS transistor, a voltage amplifying circuit thatamplifies or attenuates the reference potential to a potential of anarbitrary ratio, a leakage current detection first main conductivity MIStransistor with a source connected to the first power supply, a drainconnected to a third current source, and a potential amplified by thevoltage amplifying circuit applied to a gate, and substrate voltagecontrolled by the substrate voltage control block. Here, the first,second and fourth first main conductivity MIS transistors operate in asub-threshold region in such a manner that an absolute value of adifference in gate potential of the first first main conductivity MIStransistor, the second first main conductivity MIS transistor, and thefourth first main conductivity MIS transistor becomes equal to orsmaller than a threshold voltage of the first, second, and fourth firstmain conductivity MIS transistors, and the threshold voltage iscontrolled by inputting a signal based on fluctuation in drain potentialof the leakage current detection first main conductivity MIS transistorto the substrate voltage control block.

According to another aspect of the present invention, an electronicapparatus comprises a semiconductor integrated circuit apparatus havinga power supply apparatus and a threshold voltage control function. Here,the semiconductor integrated circuit is constituted by the semiconductorintegrated circuit apparatus described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the invention will appearmore fully hereinafter from a consideration of the following descriptiontaken in connection with the accompanying drawings in which;

FIG. 1 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 1 of the present invention;

FIG. 2 shows a circuit configuration for a controller of a semiconductorintegrated circuit apparatus according to Embodiment 1;

FIG. 3 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 2 of the present invention;

FIG. 4 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 3 of the present invention;

FIG. 5 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 4 of the present invention;

FIG. 6 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 5 of the present invention;

FIG. 7 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 6 of the present invention;

FIG. 8 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 7 of the present invention;

FIG. 9 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 8 of the present invention;

FIG. 10 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 9 of the present invention;

FIG. 11 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 10 of the present invention;

FIG. 12 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 11 of the present invention;

FIG. 13 shows a circuit configuration for a controller of asemiconductor integrated circuit apparatus according to Embodiment 11;

FIG. 14 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 12 of the present invention;

FIG. 15 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 13 of the present invention;

FIG. 16 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 14 of the present invention;

FIG. 17 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 15 of the present invention;

FIG. 18 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 16 of the present invention;

FIG. 19 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 17 of the present invention;

FIG. 20 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 18 of the present invention;

FIG. 21 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 19 of the present invention;

FIG. 22 is a block view showing a configuration of an electronicapparatus according to Embodiment 20 of the present invention;

FIG. 23 shows a configuration for a semiconductor integrated circuitapparatus controlling threshold voltage of an NchMOS transistor of therelated art; and

FIG. 24 shows the relationship between V_(g), V_(b) and I_(b) ofsemiconductor integrated circuit apparatus of the related art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention using MOS transistors that aretypical examples of MIS transistors will be described below in detailwith reference to the accompanying drawings.

(Description of Theory)

First, the basic theory of the present invention will be described.

A semiconductor integrated circuit apparatus controlling transistorthreshold voltage of the present invention comprises a leakage currentdetection block, substrate voltage control block, and internal circuit,with the leakage current detection block having the following circuitconfiguration. First, in order to resolve the first problem, leakagecurrent detection NchMOS transistor T_(n1) with a source connected tolow potential side supply voltage V_(SS), a drain connected to aconstant current source, and a substrate voltage controlled by a voltagegenerated by the substrate voltage control block is formed. Next, aconfiguration is adopted where NchMOS transistor T_(n6) and NchMOStransistor T_(n7) are connected in series, the source of NchMOStransistor T_(n6) is connected to low potential side supply voltageV_(SS), the drain of NchMOS transistor T_(n7) is connected to a separateconstant current source, the gates of the two NchMOS transistors T_(n6)and T_(n7) connected together in series are connected in common andconnected to the drain of NchMOS transistor T_(n7), a stable potentialV_(g2) is taken from the center of the two NchMOS transistors, the draincurrent of NchMOS transistor T_(n5) taking this potential V_(g2) as agate potential is amplified to a current value of an arbitrary ratiousing a current mirror circuit, this current value flows through NchMOStransistor T_(n2) with a gate and drain connected together, and drainpotential V_(g1) of this transistor is applied to the gate of leakagecurrent detection NchMOS transistor T_(n1).

As a separate circuit configuration, it is also possible to obtainV_(g1) amplified by an arbitrary ratio from potential V_(g2) by using avoltage amplifying circuit using operational amplifiers instead of thecurrent mirror circuit.

As a further configuration for a reference voltage generating circuit, aconfiguration may be adopted where a drain voltage of NchMOS transistorT_(n8) with a gate and drain connected to a separate constant currentsource, and a source connected to low potential side supply voltageV_(SS) is applied to gate potential V_(g3) of NchMOS transistors T_(n6)and T_(n7) generating the reference potential.

Further, as a separate configuration for a leakage current detectioncircuit, rather than using leakage current detection NchMOS transistorT_(n1) connected as a circuit as described above, a source followercircuit comprised of leak current detection NchMOS transistor T_(n21)where a drain is connected to a high potential side supply voltageV_(DD), a source is connected to a constant current source, andsubstrate voltage is controlled by a substrate voltage control block isused. The leakage current can then be similarly detected by comparingthe source potential of leakage current detection NchMOS transistorT_(n21) with low potential side supply voltage V_(SS) that is areference potential using a comparator.

Further, it is also possible to similarly detect leakage current in ahighly precise manner with a circuit configuration where a switch isinserted between the source potential and low potential side supplyvoltage V_(SS) constituted by the reference potential and inputs IN1 andIN2 of a comparator, and then a DC offset of the comparator iscancelled.

Moreover, as a further configuration for a leakage current detectioncircuit, it is possible to similarly detect leakage current by carryingout potential comparison by a comparator to compare drain potential ofleakage current detection NchMOS transistor T_(n31) with a sourceconnected to low potential side supply voltage V_(SS), a gate and drainconnected together and connected to a constant current source and asubstrate voltage controlled by a substrate voltage control block and anoutput of a voltage amplifier using the current mirror circuit oroperational amplifiers.

Further, it is also possible to detect leakage current in a highlyprecise manner with a circuit configuration where a switch is insertedbetween the output of the drain potential and a voltage amplifier usingthe current mirror circuit or operational amplifiers and inputs IN1 andIN2 of a comparator, and then a DC offset of the comparator iscancelled.

With the above circuit configuration, as it is possible to increase thedetection current value of leakage current detection NchMOS transistorT_(n1) by an arbitrary ratio, detection of leakage current, comparisonof the detected leakage current and target current value anddetermination of the result after comparison are extremelystraightforward. In addition, it is possible to accelerate the responseto substrate voltage control so that fluctuation of substrate voltagecan also be suppressed.

Further, in order to resolve the second problem, it is possible to keepthe power consumed when the leakage current detection circuit is notoperating low by using a control signal at a circuit constituting aconstant current source of the leakage current detection circuit andputting the constant current source on or off.

Further, in order to resolve the third problem, it is possible toarbitrarily change the threshold voltage according to a changing systemclock frequency or supply voltage by ensuring that the currentamplification ratio of the current mirror circuit and the voltageamplification ratio of the voltage amplifying circuit using operationalamplifiers are made to vary according to the system clock frequency orsupply voltage.

Further, with CMOS (Complementary Metal Oxide Semiconductor) circuit, itis possible to achieve high speeds and low power consumption for theintegrated circuit as a whole by providing threshold voltage controlcircuit apparatus at the NchMOS transistor and PchMOS transistor,respectively.

Embodiment 1

FIG. 1 shows a configuration for a semiconductor integrated circuitapparatus controlling a threshold voltage of a transistor according toEmbodiment 1 of the present invention based on the aforementioned basicconcepts. This embodiment shows an example applied to a semiconductorintegrated circuit apparatus equipped with an NchMOS transistor leakagecurrent detection block, substrate voltage control block, and internalcircuit.

In FIG. 1, semiconductor integrated circuit apparatus 100 is equippedwith NchMOS transistor leakage current detection block 110, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 100 adopts a basicconfiguration employing leakage current detection NchMOS transistorT_(n1) with a drain connected to a constant current source for leakagecurrent detection of the NchMOS transistor T_(n (LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 110 is comprised of reference voltagegenerating circuit 111, current mirror circuit 112, and leakage currentdetection circuit 113. Leakage current detection block 110 arbitrarilyamplifies a leakage current value of leakage current detection NchMOStransistor T_(n1) of leakage current detection circuit 113 using currentmirror circuit 112, and makes detection of leakage current anddetermination straightforward. Further, it is possible to accelerate theresponse to substrate voltage control so that fluctuation of substratevoltage can be suppressed.

Moreover, the configuration is such that current does not pass throughleakage current detection circuit 113 when leakage current detectioncircuit 113 is not operating.

[Circuit Configuration of Reference Voltage Generating Circuit 111]

Reference voltage generating circuit 111 is comprised of NchMOStransistor T_(n9) receiving control signal N from substrate voltagecontrol block 120 at a gate, PchMOS transistor T_(p9) connected to thedrain of NchMOS transistor T_(n9), PchMOS transistor T_(p6) with thedrain of NchMOS transistor T_(ng) connected to the gate, and NchMOStransistor T_(n7) and NchMOS transistor T_(n6) connected in series withPchMOS transistor T_(p6).

Looked at functionally, reference voltage generating circuit 111 iscomprised of NchMOS transistor T_(n6) and NchMOS transistor T_(n7)constituting voltage generating section 111 a that generates a potentialfor generating gate potential V_(g1) of leakage current detection NchMOStransistor T_(n1) of leakage current detection circuit 113, and NchMOStransistor T_(n9), PchMOS transistor T_(p9), PchMOS transistor T_(p6)and PchMOS transistor T_(p1) of leakage current detection circuit 113constituting constant current source 111 b that supplies a constantcurrent to this NchMOS transistor T_(n6) and NchMOS transistor T_(n7).

In voltage generating section 111 a of reference voltage generatingcircuit 111, NchMOS transistor T_(n6) and NchMOS transistor T_(n7) areconnected in series, the source of NchMOS transistor T_(n6) is connectedto low potential side supply voltage V_(SS), the drain of NchMOStransistor T_(n7) is connected to a separate constant current source 111b, this substrate is connected to the source of NchMOS transistorT_(n7), and the gates of NchMOS transistor T_(n6) and NchMOS transistorT_(n7) respectively are connected in common and connected to the drainof NchMOS transistor T_(n7). Drain potential V_(g2) of NchMOS transistorT_(n6) is applied to the gate of NchMOS transistor T_(n5). PotentialV_(g2) of the drain of NchMOS transistor T_(n6) and the source of NchMOStransistor T_(n7) constitutes the generated potential of referencevoltage generating circuit 111. The relationship between the gatepotential V_(g3) of NchMOS transistor T_(n6) and NchMOS transistorT_(n7) and the above potential V_(g2) will be described later.

As an example circuit of constant current source 111 b, this embodimentis comprised of NchMOS transistor T_(n9) with a source connected to lowpotential side supply voltage V_(SS) and control signal N received at agate, PchMOS transistor T_(p9) with a source connected to high potentialside supply voltage V_(DD), and a gate and drain connected to the drainof NchMOS transistor T_(n9), and PchMOS transistor T_(p6) and PchMOStransistor T_(p1) constituting a current mirror circuit with PchMOStransistor T_(p9).

It is then possible to keep the power consumed when leakage currentdetection circuit 113 is not operating low by controlling NchMOStransistor T_(n9) within the circuit constituting constant currentsource 111 b of leakage current detection circuit 113 using controlsignal N.

[Circuit Configuration of Current Mirror Circuit 112]

Current mirror circuit 112 is comprised of NchMOS transistor T_(n5)receiving generated potential V_(g2) of reference voltage generatingcircuit 111 at a gate, PchMOS transistor T_(p5) and PchMOS transistorT_(p4) connected to the drain of NchMOS transistor T_(n5), NchMOStransistor T_(n4) and NchMOS transistor T_(n3) connected to the drain ofPchMOS transistor T_(p4) PchMOS transistor T_(p3) and PchMOS transistorT_(p2) connected to the drain of NchMOS transistor T_(n3), and NchMOStransistor T_(n2) connected to the drain of PchMOS transistor T_(p2).

Looked at functionally, current mirror circuit 112 is comprised of aplurality of stages of current mirror circuits where the gates arecommon, the sources are at the same potential, and transistorsconstituting pairs operate under the same operating conditions.Specifically, the current mirror circuit has a plurality of stagescomprised of first current mirror circuit 112 a composed of PchMOStransistor T_(p5) and PchMOS transistor T_(p4) connected to the drain ofNchMOS transistor T_(n5) second current mirror circuit 112 b composed ofNchMOS transistor T_(n4) and NchMOS transistor T_(n3) connected to thedrain of PchMOS transistor T_(p4), third current mirror circuit 112 ccomposed of PchMOS transistor T_(p3) and PchMOS transistor T_(p2)connected to the drain of NchMOS transistor T_(n3), and fourth currentmirror circuit 112 d composed of NchMOS transistor T_(n2) and leakagecurrent detection Nch transistor T_(n1) connected to the drain of PchMOStransistor T_(p2).

Of current mirror circuits 112 a to 112 d of the plurality of stages,first current mirror circuit 112 a, second current mirror circuit 112 band third current mirror circuit 112 c are current amplifier circuitsfor amplifying drain current I₅ of NchMOS transistor T_(n5) takinggenerated potential V_(g2) of reference voltage generating circuit 111as a gate potential to a current value of an arbitrary ratio and flowingthrough NchMOS transistor T_(n2). Fourth current mirror circuit 112 d isa circuit for extracting drain potential V_(g1) of NchMOS transistorT_(n2) when drain current I₂ flows through NchMOS transistor T_(n2) withthe gate and drain common and applying this potential to leakage currentdetection NchMOS transistor T_(n1).

Current mirror circuit 112 has superior features in that (1) a separatepower supply is not required, (2) drain current can be amplified by anarbitrary ratio by changing the physical size of the transistor,specifically, the channel width W etc. which will be described later,(3) a multi-stage configuration (in this case, 3 stages) is possible,and (4) there is no influence due to fluctuation in supply voltage,temperature and process variations during leak current detection.Further, in the case of application to leakage current detection block110, (5) the ratio of the current value of drain current I₅ flowingthrough NchMOS transistor T_(n5) and the current value of NchMOStransistor T_(n (LSI)) of internal circuit 130 can be theoreticallycontrolled by the transistor size. Therefore, there is no influence dueto fluctuation in supply voltage, temperature and process variationsduring leakage current detection (to be described in detail later).Namely, by using a current mirror circuit, an effect is obtained thatdetection and determination can be straightforward by amplifyingarbitrarily set leakage detection current values, and it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed. It is also possible tocontrol the ratio of the value of drain current flowing through NchMOStransistor T_(n1) and the current value of NchMOS transistor T_(n (LSI))of internal circuit 130 so that there is therefore no influence due tofluctuation in supply voltage, temperature and process variations duringleakage current detection.

In this embodiment, by giving a current mirror circuit for amplifying aleakage detection current value as a three stage configuration (currentmirror circuits 112 a to 112 c), it is possible to employ a currentmirror circuit using normal transistor size and implementation isstraightforward.

[Circuit Configuration of Leakage Current Detection Circuit 113]

Leakage current detection circuit 113 is comprised of leakage currentdetection NchMOS transistor T_(n1) receiving potential V_(g1) at a gate,PchMOS transistor T_(p1) connected in series with leakage currentdetection NchMOS transistor T_(n1), OR gate circuit G1, and invertercircuit G2.

Leakage current detection NchMOS transistor T_(n1) with a drainconnected to OR gate circuit G1, a source connected to low potentialside supply voltage V_(SS), a gate connected to the gate of NchMOStransistor T_(n2) of current mirror circuit 112, constitutes the fourthcurrent mirror circuit 112 d with NchMOS transistor T_(n2).

Further, PchMOS transistor T_(p1) with a source connected to highpotential side supply voltage V_(DD) and a drain connected to leakagecurrent detection NchMOS transistor T_(n1), and constitutes a currentmirror circuit with PchMOS transistor T_(p9) of reference voltagegenerating circuit 111.

[Circuit Configuration of Substrate Voltage Control Block 120]

Substrate voltage control block 120 is comprised of controller 121controlling substrate voltage by an operation mode signal from outside,and DA converter 122 D/A converting a digital value from controller 121and generating a substrate voltage.

FIG. 2 shows a circuit configuration for controller 121. In FIG. 1 andFIG. 2, controller 121 is comprised of up-down counter 123, register 124(register 1), substrate voltage setting upper limit value register 125,substrate voltage setting lower limit value register 126, comparatorcircuit 127, register 128 (register 2), and control circuit 129.

Controller 121 carries out control to change substrate voltage appliedto the substrate of leakage current detection NchMOS transistor T_(n1)and the substrate of the NchMOS transistors of internal circuit 130 bychanging a count value of the up-down counter based on the output ofgate circuit G1. DA converter 122 DA converts a digital value fromcontroller 121 and generates a substrate voltage.

The value of register 2 from controller 121 is inputted to DA converter122, and a substrate voltage corresponding to register 2 from DAconverter 122 is applied to the substrate of leakage current detectionNchMOS transistor T_(n1) and the substrate of the NchMOS transistor ofinternal circuit 130. Further, DA converter 122 generates a substratevoltage via a buffer using, for example, an operational amplifier (animpedance converter circuit with an output of the DA converter connectedto a + input terminal of an operational amplifier, and with the − inputterminal and output terminal of the operational amplifier connected).

Internal circuit 130 may be any kind of circuit providing a circuitwhere threshold voltages of NchMOS transistors of the internal circuitare controlled by semiconductor integrated circuit apparatus 100, buthere a CMOS circuit where gates of a PchMOS transistor and an NchMOStransistor connected in series are common is adopted as an example.

The above leakage current detection NchMOS transistor T_(n1) may bearranged on the same substrate as the NchMOS transistor of internalcircuit 130 or arranged on a separate substrate, and electricallyconnected.

A substrate voltage control operation for semiconductor integratedcircuit apparatus 100 of the configuration described above will bedescribed below. First, the operation of each block will be described,and followed by that, the threshold voltage control operation bysubstrate voltage control, and the theory of detecting leakage currentI_(L.LCM) will be described.

[Operation of Leakage Current Detection Block 110]

(1) Operation of Reference Voltage Generating Circuit 111

First, at reference voltage generating circuit 111, a stable potentialV_(g2) is generated from the center of T_(n6) and T_(n7) as a result ofNchMOS transistors T_(n6) and T_(n7) connected in series being made tooperate in the sub-threshold region, and is applied to the gate ofNchMOS transistor T_(n5) of current mirror circuit 112.

(2) Operation of Current Mirror Circuit 112

At first current mirror circuit 112 a of current mirror circuit 112,drain current I₅ of NchMOS transistor T_(n5) is amplified by anarbitrary ratio (for example, ten times). The drain of PchMOS transistorT_(p4) is connected to NchMOS transistor T_(n4) constituting the secondcurrent mirror circuit 112 b, and at the second current mirror circuit112 b, drain current I₄ amplified ten times by first current mirrorcircuit 112 a of the front stage is further amplified by an arbitraryratio (for example, ten times). The drain of NchMOS transistor T_(n3) isconnected to PchMOS transistor T_(p3) constituting the third currentmirror circuit 112 c, and at the third current mirror circuit 112 c,drain current I₃ amplified up to 100 times by second current mirrorcircuit 112 b of the front stage is further amplified by an arbitraryratio (for example, ten times). As a result, the current value of draincurrent I₂ of NchMOS transistor T_(n2) becomes the current value ofdrain current I₅ of NchMOS transistor T_(n5) amplified by an arbitraryratio (in this case, 1000 times).

NchMOS transistor T_(n3) of current mirror circuit 112 constitutesfourth current mirror circuit 112 d with leakage current detectionNchMOS transistor T_(n1)of leakage current detection circuit 113, anddrain potential V_(g1) of NchMOS transistor T_(n2) at the time draincurrent I₂ flows through NchMOS transistor T_(n2) where a gate and drainare common is applied to the gate of leakage current detection NchMOStransistor T_(n1).

The drain current I₂ of NchMOS transistor T_(n2) is a current value thatis the detection current value of drain current I₅ of NchMOS transistorT_(n5) amplified 1000 times by current mirror circuits 112 a to 112 cand a potential V_(g1) close to the threshold voltage of leakage currentdetection NchMOS transistor T_(n1) is applied to leakage currentdetection NchMOS transistor T_(n1) constituting current mirror circuit112 d together with NchMOS transistor T_(n2). Therefore, as it ispossible that leakage current detection NchMOS transistor T_(n1) carriesout a detection operation using an appropriate operation level,detection of leakage current, comparison of the detected leakage currentand target current value and determination of the result aftercomparison are extremely straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed.

(3) Operation of Leakage Current Detection Circuit 113

The drain of leakage current detection NchMOS transistor T_(n1) isinputted to gate circuit G1, and a digital signal is outputted from gatecircuit G1. Further, at gate circuit G1, control signal N fromcontroller 121 of substrate voltage control block 120 is inputted, andif there is no other control signal N (if control signal N is an Llevel), gate circuit G1 becomes a buffer circuit or inverter circuit,and if there is control signal N, gate circuit G1 becomes an OR/NORcircuit or AND/NAND circuit. In Embodiment 1, an OR circuit is used. Theoutput of gate circuit G1 is inputted to controller 121 of substratevoltage control block 120 as detection signal N. Control signal N ofcontroller 121 is connected to the gate of PchMOS transistor T_(p9)constituting constant current source 111 b of leakage current detectioncircuit 113, and when leakage current detection circuit 113 is notoperating, current is made not to flow through leakage current detectioncircuit 113 and the power consumed when leakage current detectioncircuit 113 is not operating can therefore be kept low. At this time, inorder to prevent a situation where each of the transistors constitutingthe above constant current source 111 b becomes a high-impedance stateso as to cause circuit operation to become unstable, controller 121inputs control signal N to gate circuit G1 so as to stop operation ofthis portion of the circuit.

[Operation of Substrate Voltage Control Block 120]

Substrate voltage control block 120 includes two types, namely an analogscheme circuit and a digital scheme circuit, but here, an example ofdigital circuit will be described. As shown in FIG. 2, substrate voltagecontrol block 120 is comprised of controller 121 comprised of up-downcounter 123 controlling substrate voltage, register 124 (register 1),substrate voltage setting upper limit value register 125, substratevoltage setting lower limit value register 126, comparator circuit 127,register 128 (register 2) and control circuit 129, and DA converter 122receiving a digital value from controller 121 and generating a substratevoltage. Control circuit 129 receives an operation mode signal andcontrols up-down counter 123 and registers 124 and 128. Further, controlcircuit 129 outputs control signal N to leakage current detection block110. Control signal N is inputted to OR gate circuit G1 via invertercircuit G2, and operates of cutting current flowing through and fixingthe output of OR gate circuit G1 at a high level when the leakagecurrent detection block 110 is not operating. Substrate voltagegenerated by DA converter 122 is applied to the substrate of NchMOStransistor T_(n (LSI)) equivalently representing the substrate ofleakage current detection NchMOS transistor T_(n1) and internal circuit130.

Next, the threshold voltage control operation using substrate voltagecontrol will be described.

In this embodiment, before starting the substrate voltage controloperation, an up-down count value and register value are reset to zero(0) or are set to the value measured the previous time. Next, whencontrol signal N becomes a high level (H), leakage current detectioncircuit 113 starts to operate. If drain current of leakage currentdetection NchMOS transistor T_(n1) is smaller than a target currentvalue generated by PchMOS transistor T_(p1) constituting constantcurrent source 111 b, detection signal N outputted from OR gate circuitG1 becomes a high level, up-down counter 123 counts up, and a countvalue is stored in register 1. Comparator circuit 127 compares whetheror not the inputted signal from register 1 exceeds the substrate voltagesetting upper limit value or lower limit value, and stores the resultsof the comparison in register 2. DA converter 122 then outputs asubstrate voltage corresponding to the value of register 2, and raises(makes shallow) the substrate voltage of leakage current detectionNchMOS transistor T_(n1). As a result, the threshold voltage of leakagecurrent detection NchMOS transistor T_(n1) becomes small, and the draincurrent of NchMOS transistor T_(n1) becomes large.

Conversely, if the drain current of leakage current detection NchMOStransistor T_(n1) is larger than a target current value, detectionsignal N becomes a low level, up-down counter 123 counts down, and thecount value is stored in register 1. Comparator circuit 127 compareswhether or not the inputted signal from register 1 exceeds the substratevoltage setting upper limit value or lower limit value, and stores theresults of the comparison in register 2. DA converter 122 then outputs asubstrate voltage corresponding to the value of register 2, and lowers(deepens) the substrate voltage of leakage current detection NchMOStransistor T_(n1). As a result, the threshold voltage of leakage currentdetection NchMOS transistor T_(n1) becomes large, and the drain currentof NchMOS transistor T_(n1) becomes small.

By repeating the above operation, the drain current of leakage currentdetection NchMOS transistor T_(n1) finally converges to become the sameas the target current value. If the drain current converges on thetarget current value, by fixing the value of register 2, stopping theoperation of up-down counter 123, and making control signal N to L, itis also possible to fix the output of the OR gate circuit to a highlevel so as to ensure that current does not flow through leakage currentdetection circuit 113 and so as to prevent erroneous operation.

Further, when the internal circuit does not operate, for example at thetime of turning on the power supply or in test mode, a threshold voltagecontrol operation is carried out and values obtained for register 2 aresaved, and at the time of normal operation mode, threshold voltagecontrol of the internal circuit can be carried out using the value ofregister 2.

The lower limit of the output of substrate voltage control block 120 ispreferably set to a voltage of a range where a GIDL (Gate-Induced DrainLeakage) effect does not occur at the NchMOS transistor. The GIDL effectis an effect where sub-threshold current increases when a back-bias thatis a negative voltage to the substrate is excessively applied.

Further, the upper limit of the output of substrate voltage controlblock 120 is preferably set to a voltage of a range where the MOStransistor does not show bipolar characteristics. When a forward biasthat is a positive voltage to the substrate is excessively applied, theMOS transistor shows a bipolar characteristic, the gain of the feedbackof the threshold control circuit becomes extremely large, and thefeedback system oscillates. Therefore, it is necessary to prevent theabove.

Next, the capability that the ratio of the current value of a leakagecurrent detection NchMOS transistor and the current value of the NchMOStransistor of internal circuit 130 can be controlled theoretically usingtransistor size will be described. In this way, there is no influencedue to fluctuation in supply voltage, temperature and process variationsduring leakage current detection.

The relationship between leakage current I_(L.LSI) of the NchMOStransistor T_(n (LSI)) equivalently representing internal circuit 130and leakage current I_(L.LCM) of leakage current detection NchMOStransistor T_(n1) will be described.

In FIG. 1, the current value I₆ of the constant current source isadjusted in such a manner that NchMOS transistor T_(n6) and NchMOStransistor T_(n7) of reference voltage generating circuit 111 operate inthe sub-threshold region. Further, channel width of NchMOS transistorT_(n6) is taken to be W₁, and channel width of NchMOS transistor T_(n7)is taken to be W₂. At this time, a potential difference between gatepotential V_(g3) of NchMOS transistor T_(n6) and potential V_(SS) istaken to be equal to or smaller than the threshold voltage of NchMOStransistor T_(n6) and NchMOS transistor T_(n7).

Drain current of NchMOS transistor operating in the sub-threshold regionis represented by the following equation (1).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack & \; \\{I_{DS} = {\frac{I_{0}}{W_{0}}{W \cdot 10^{{({V_{GS} - V_{rc}})}/S}}}} & (1)\end{matrix}$

Here, W is channel width, V_(cs) is gate-source voltage, V_(TC) isV_(GS) (threshold voltage) at the time drain current I₀ starts to flowthrough an MOS transistor of channel width W₀. S is referred to as “Sparameter,” and indicates the value of V_(GS) required to lower theleakage current by one decimal place. This S parameter can berepresented by the following equation (2).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack & \; \\{S = {\frac{kT}{q}\left( {1 + \frac{C_{DP}}{C_{OX}}} \right)\ln \; 10}} & (2)\end{matrix}$

Therefore, the leakage current value of the NchMOS transistorT_(n (LSI)) of internal circuit 130 can be represented by the followingequation (3).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack & \; \\{I_{L.{LSI}} = {\frac{I_{0}}{W_{0}}{W_{LSI} \cdot 10^{{- V_{rc}}/S}}}} & (3)\end{matrix}$

The leakage current detected by leakage current detection NchMOStransistor T_(n1) can be expressed by equation (4) based on equation(1).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack & \; \\{I_{L.{LCM}} = {\frac{I_{0}}{W_{0}}{W_{LCM} \cdot 10^{{({V_{{g\; 1}\;} - V_{rc}})}/S}}}} & (4)\end{matrix}$

With NchMOS transistor T_(n6) and NchMOS transistor T_(n7) ofsemiconductor integrated circuit apparatus 100 according to Embodiment1, drain current can be expressed using equation (1), and as both areequal, the following equation (5) is satisfied.

[Equation 5]

W ₁·10^((V) ^(g1) ^(−V) ^(TC1) ^()/S) =W ₂·10^((V) ^(g1) ^(−V) ^(g2)^(−V) ^(TC2) ^()/S)  (5)

Here, V_(TC1) is the threshold voltage of T_(n6) and V_(TC2) is thethreshold voltage of T_(n7). Gate potential V_(g2) can therefore beexpressed using the following equation (6).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack & \; \\{V_{g\; 2} = {{\left( {V_{{TC}\; 1} - V_{{TC}\; 2}} \right) + {{S \cdot \log}\frac{W_{2}}{W_{1}}}} \approx {{S \cdot \log}\frac{W_{2}}{W_{1}}}}} & (6)\end{matrix}$

Further, assuming that the channel width ratio of PchMOS transistorsT_(p3) and T_(p2) (third current mirror circuit 112 c) constituting thecurrent mirror circuits of current mirror circuit 112 from NchMOStransistors T_(n2) to T_(n5), NchMOS transistors T_(n4) and T_(n3)(second current mirror circuit 112 b), and PchMOS transistors T_(p5) andT_(p4) (first current mirror circuit 112 a) is ten times or one tenth ofthe channel length ratio, the current value of current I₂ becomes acurrent value that is 1000 times the current value of current I₅, andgate potential V_(g1) can be expressed by the following equation (7).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack & \; \\{V_{g\; 1} = {{V_{g\; 2} + {3\; S}} = {S\left( {{\log \frac{W_{2}}{W_{1}}} + 3} \right)}}} & (7)\end{matrix}$

Leakage current detection power of leakage current of NchMOS transistorT_(n (LSI)) of internal circuit 130 and leakage current detection NchMOStransistor T_(n1) can then be expressed by the following equation (8).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack & \; \\{\frac{I_{L.{LSI}}}{I_{L.{LCM}}} = {{\frac{W_{LSI}}{L_{LCM}} \cdot 10^{- {({{\log \frac{W_{2}}{W_{1}}} + 3})}}} = {\frac{W_{LSI}}{L_{LCM}} \cdot \frac{W_{1}}{W_{2}} \cdot 10^{- 3}}}} & (8)\end{matrix}$

As can be seen from equation (8), the leakage current detection ratiohas no influence due to fluctuation in supply voltage and temperatureand process variations during leakage current detection so that it ispossible to design the leakage current detection ratio by the ratio ofchannel width W₁ and W₂ of NchMOS transistor T_(n6) and NchMOStransistor T_(n7). Further, it is possible to increase the leakagedetection current value of leakage current detection NchMOS transistorT_(n1) by just an amount to increase the current value by an arbitraryratio using the current mirror circuit.

In this embodiment, the substrates of NchMOS transistor T_(n6) andNchMOS transistor T_(n7) are electrically separated, but it is possibleto connect the same substrate. In this event, an approximation ofequation (6) is no longer satisfied and leakage current detection ratiois slightly dependant on temperature, but employment in practical usesis possible.

Embodiment 2

Embodiment 2 shows an example applied to a leakage current detectioncircuit using a leakage current detection PchMOS transistor.

FIG. 3 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 2 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 3, semiconductor integrated circuit apparatus 200 is equippedwith PchMOS transistor leakage current detection block 210, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 200 adopts a basicconfiguration employing leakage current detection PchMOS transistorT_(p51) with a drain connected to a constant current source for leakagecurrent detection of PchMOS transistor T_(p (LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 210 is comprised of reference voltagegenerating circuit 211, current mirror circuit 212, and leakage currentdetection circuit 213. Leakage current detection block 210 arbitrarilyamplifies a leakage current value of leakage current detection PchMOStransistor T_(p51) of leakage current detection circuit 213 usingcurrent mirror circuit 212, and makes detection of leakage current anddetermination straightforward. Further, it is possible to accelerate theresponse to substrate voltage control so that fluctuation of substratevoltage can also be suppressed. Moreover, the configuration is such thatcurrent does not pass through leakage current detection circuit 213 whenleakage current detection circuit 213 is not operating.

[Circuit Configuration of Reference Voltage Generating Circuit 211]

Reference voltage generating circuit 211 is comprised of PchMOStransistor T_(p59) receiving control signal P from substrate voltagecontrol block 120 at a gate, NchMOS transistor T_(n59) connected to thedrain of PchMOS transistor T_(p59), NchMOS transistor T_(n56) with thedrain of NchMOS transistor T_(n59) connected to the gate, and PchMOStransistor T_(p56) and PchMOS transistor T_(p57) connected in serieswith NchMOS transistor T_(n56).

Looked at functionally, reference voltage generating circuit 211 iscomprised of PchMOS transistor T_(p56) and PchMOS transistor T_(p57)constituting voltage generating section 211 a that generates a potentialfor generating gate potential V_(g11) of leakage current detectionPchMOS transistor T_(p51) of leakage current detection circuit 213, andPchMOS transistor T_(p59), NchMOS transistor T_(n59), NchMOS transistorT_(n56) and NchMOS transistor T_(n51) of leakage current detectioncircuit 213 constituting constant current source 211 b that supplies aconstant current to this PchMOS transistor T_(p56) and PchMOS transistorT_(p57).

In voltage generating section 211 a of reference voltage generatingcircuit 211, PchMOS transistor T_(p56) and PchMOS transistor T_(p57) areconnected in series, the source of NchMOS transistor T_(n56) isconnected to high potential side supply voltage V_(DD), the drain ofPchMOS transistor T_(p57) is connected to a separate constant currentsource 211 b, this substrate is connected to the source of PchMOStransistor T_(p57), and the gates of PchMOS transistor T_(p56) andPchMOS transistor T_(p57) respectively are connected in common andconnected to the drain of PchMOS transistor T_(p57). Drain potentialV_(g22) of PchMOS transistor T_(p56) is applied to the gate of PchMOStransistor T_(p55). Potential V_(g12) of the drain of PchMOS transistorT_(p56) and the source of PchMOS transistor T_(p57) constitutes thegenerated potential of reference voltage generating circuit 211. Therelationship between the gate potential V_(g13) of PchMOS transistorT_(p56) and PchMOS transistor T_(p57), and the above potential V_(g12)is the same as Embodiment 1.

As an example circuit of constant current source 211 b, this embodimentis comprised of PchMOS transistor T_(p59) with a source connected tohigh potential side supply voltage V_(DD) and control signal P receivedat a gate, NchMOS transistor T_(n59) with a source connected to lowpotential side supply voltage V_(SS), and a gate and drain connected tothe drain of PchMOS transistor T_(p59), and NchMOS transistor T_(n56)and NchMOS transistor T_(n51) constituting a current mirror circuit withNchMOS transistor T_(n59).

It is then possible to keep the power consumed when leakage currentdetection circuit 213 is not operating low by controlling PchMOStransistor T_(p59) within the circuit constituting constant currentsource 111 b of leakage current detection circuit 213 using controlsignal P.

[Circuit Configuration of Current Mirror Circuit 212]

Current mirror circuit 212 is comprised of PchMOS transistor T_(p55)receiving generated potential V_(g12) of reference voltage generatingcircuit 211 at a gate, NchMOS transistor T_(n55) and NchMOS transistorT_(n54) connected to the drain of PchMOS transistor T_(p55), PchMOStransistor T_(p54) and PchMOS transistor T_(p53) connected to the drainof NchMOS transistor T_(n54), NchMOS transistor T_(n53) and NchMOStransistor T_(n52) connected to the drain of PchMOS transistor T_(p53),and PchMOS transistor T_(p52) connected to the drain of NchMOStransistor T_(n52).

Further looked at functionally, current mirror circuit 212 has aplurality of stages comprised of first current mirror circuit 212 acomposed of NchMOS transistor T_(n55) and NchMOS transistor T_(n54)connected to the drain of PchMOS transistor T_(P55), second currentmirror circuit 212 b composed of PchMOS transistor T_(p54) and PchMOStransistor T_(p53) connected to the drain of NchMOS transistor T_(n54)third current mirror circuit 212 c composed of NchMOS transistor T_(n53)and NchMOS transistor T_(n52) connected to the drain of PchMOStransistor T_(p53), and fourth current mirror circuit 212 d composed ofPchMOS transistor T_(p52) and leakage current detection Pch transistorT_(p51) connected to the drain of NchMOS transistor T_(n52).

Of the current mirror circuits 212 a to 212 d of the plurality ofstages, first current mirror circuit 212 a, second current mirrorcircuit 212 b and third current mirror circuit 212 c are currentamplifier circuits for amplifying drain current I₁₅ of PchMOS transistorT_(p55) taking generated potential V_(g12) of reference voltagegenerating circuit 211 as a gate potential to a current value of anarbitrary ratio and flowing through PchMOS transistor T_(p52). Fourthcurrent mirror circuit 212 d is a circuit for extracting drain potentialV_(g11) of PchMOS transistor T_(p52) when drain current I₁₂ flowsthrough PchMOS transistor T_(p52) with the gate and drain common andapplying this potential to leakage current detection PchMOS transistorT_(p51).

As in Embodiment 1, each current mirror circuit 212 a to 212 c canamplify the current values by an arbitrary ratio depending on thedesign.

[Circuit Configuration of Leakage Current Detection Circuit 213]

Leakage current detection circuit 213 is comprised of leakage currentdetection PchMOS transistor T_(p51) receiving potential V_(g11) at agate, NchMOS transistor T_(n51) connected in series with leakage currentdetection PchMOS transistor T_(p51), and OR gate circuit G51.

Leakage current detection PchMOS transistor T_(p51) with a drainconnected to OR gate circuit G51, a source connected to high potentialside supply voltage V_(DD), and a gate connected to the gate of PchMOStransistor T_(p52) of current mirror circuit 212 constitutes the fourthcurrent mirror circuit 212 d with PchMOS transistor T_(p52).

Further, NchMOS transistor T_(n51) with a source connected to lowpotential side supply voltage V_(SS) and a drain connected to leakagecurrent detection PchMOS transistor T_(p51) constitutes a current mirrorcircuit with NchMOS transistor T_(n59) of reference voltage generatingcircuit 211.

By increasing the detection current value of leakage current detectionPchMOS transistor T_(p51), detection of leakage current, comparison ofthe detected leakage current and target current value and determinationof the result after comparison are extremely straightforward. Further,it is possible to accelerate the response to substrate voltage controlso that fluctuation of substrate voltage can also be suppressed.

Moreover, the circuit configuration of substrate voltage control block120 and internal circuit 130 is identical to those in FIG. 1 and FIG. 2,and description thereof will be omitted.

A substrate voltage control operation for semiconductor integratedcircuit apparatus 200 of the configuration described above will bedescribed.

The theory of operation is exactly the same as for FIG. 1 simply withNchMOS transistors changed for PchMOS transistors, and vice versa.

[Operation of Leakage Current Detection Block 210]

(1) Operation of Reference Voltage Generating Circuit 211

First, at reference voltage generating circuit 211, a stable potentialV_(g12) is generated from the center of T_(p56) and T_(p57) as a resultof PchMOS transistors T_(p56) and T_(p57) connected in series being madeto operate in the sub-threshold region, and is applied to the gate ofPchMOS transistor T_(p55) of current mirror circuit 212.

(2) Operation of Current Mirror Circuit 212

At first current mirror circuit 212 a of current mirror circuit 212,drain current I₁₅ of PchMOS transistor T_(p55) is amplified by anarbitrary ratio (for example, ten times). The drain of NchMOS transistorT_(n54) is connected to PchMOS transistor T_(p54) constituting thesecond current mirror circuit 212 b, and at the second current mirrorcircuit 212 b, drain current I₁₄ amplified ten times by first currentmirror circuit 212 a of the front stage is further amplified by anarbitrary ratio (for example, ten times). The drain of PchMOS transistorT_(p53) is connected to NchMOS transistor T_(n53) constituting the thirdcurrent mirror circuit 212 c, and at the third current mirror circuit212 c, drain current I₁₃ amplified up to 100 times by second currentmirror circuit 212 b of the front stage is amplified by an arbitraryratio (for example, ten times). As a result, the current value of draincurrent I₁₂ of PchMOS transistor T_(p52) becomes the current value ofdrain current I₁₅ of NchMOS transistor T_(p55) amplified by an arbitraryratio (in this case, 1000 times).

PchMOS transistor T_(p52) of current mirror circuit 212 constitutesfourth current mirror circuit 212 d with leakage current detectionPchMOS transistor T_(p51) of leakage current detection circuit 213, anddrain potential V_(g11) of PchMOS transistor T_(p52) at the time draincurrent I₁₂ flows through PchMOS transistor T_(p52) where a gate anddrain are common is applied to the gate of leakage current detectionPchMOS transistor T_(p51).

The drain current I₁₂ of PchMOS transistor T_(p52) is a current valuethat is the detection current value of drain current I₁₅ of PchMOStransistor T_(p55) amplified 1000 times by current mirror circuits 212 ato 212 c and a potential V_(g11) close to the threshold voltage ofleakage current detection PchMOS transistor T_(p51) is applied toleakage current detection PchMOS transistor T_(p51) constituting acurrent mirror circuit 212 d together with PchMOS transistor T_(p52).Therefore, as it is possible that leakage current detection PchMOStransistor T_(p51) carries out a detection operation using anappropriate operation level, detection of leakage current, comparison ofthe detected leakage current and target current value and determinationof the result after comparison are extremely straightforward. Further,it is possible to accelerate the response to substrate voltage controlso that fluctuation of substrate voltage can also be suppressed.

(3) Operation of Leakage Current Detection Circuit 213

The drain of leakage current detection PchMOS transistor T_(p51) isinputted to gate circuit G51, control signal P from controller 121 ofsubstrate voltage control block 120 is inputted, and a digital signal isoutputted from gate circuit G51. The output of gate circuit G51 isinputted to controller 121 of substrate voltage control block 120.Control signal P of controller 121 is connected to the gate of NchMOStransistor T_(n59) constituting constant current source 211 b of leakagecurrent detection circuit 213, and when leakage current detectioncircuit 213 is not operating, current is made not to flow throughleakage current detection circuit 213 and the power consumed whenleakage current detection circuit 213 is not operating can therefore bekept low. At this time, in order to prevent a situation where each ofthe transistors constituting the above constant current source 211 bbecomes a high-impedance state so as to cause circuit operation tobecome unstable, controller 121 inputs control signal P to gate circuitG51 so as to stop operation of this portion of the circuit.

[Operation of Substrate Voltage Control Block 120]

As shown in FIG. 2, substrate voltage control block 120 is comprised ofcontroller 121 with a register built-in used in substrate voltagecontrol, and DA converter 122 receiving a digital value from controller121 and generating a substrate voltage. Substrate voltage generated bysubstrate voltage control block 120 is applied to the substrate ofPchMOS transistor T_(p (LSI)) equivalently representing the substrate ofleakage current detection PchMOS transistor T_(p51) and internal circuit130.

In this embodiment, before starting the substrate voltage controloperation, an up-down count value and register value are reset to zero(0) or are set to the value measured the previous time. Next, whencontrol signal P becomes a high level (H), leakage current detectioncircuit 213 starts to operate. If drain current of leakage currentdetection PchMOS transistor T_(p51) is smaller than a target currentvalue generated by NchMOS transistor T_(n51) constituting constantcurrent source 211 b detection signal P outputted from OR gate circuitG51 becomes a high level, up-down counter 123 counts up, and a countvalue is stored in register 1. Comparator circuit 127 compares whetheror not the inputted signal from register 1 exceeds the substrate voltagesetting upper limit value or lower limit value, and stores the resultsof the comparison in register 2. DA converter 122 then outputs asubstrate voltage corresponding to the value of register 2, and raises(makes shallow) the substrate voltage of leakage current detectionPchMOS transistor T_(p51). As a result, the threshold voltage of leakagecurrent detection PchMOS transistor T_(p51) becomes small, and the draincurrent of PchMOS transistor T_(p51) becomes large.

Conversely, if the drain current of leakage current detection PchMOStransistor T_(p51) is larger than a target current value, detectionsignal P becomes a low level, up-down counter 123 counts down, and thecount value is stored in register 1. Comparator circuit 127 compareswhether or not the inputted signal from register 1 exceeds the substratevoltage setting upper limit value or lower limit value, and stores theresults of the comparison in register 2. DA converter 122 then outputs asubstrate voltage corresponding to the value of register 2, and lowers(deepens) the substrate voltage of leakage current detection PchMOStransistor T_(p51). As a result, the threshold voltage of leakagecurrent detection PchMOS transistor T_(p51) becomes large, and the draincurrent of PchMOS transistor T_(p51) becomes small.

By repeating the above operation, the drain current of leakage currentdetection PchMOS transistor T_(p51) finally converges to become the sameas the target current value. If the drain current converges on thetarget current value, by fixing the value of register 2, stopping theoperation of up-down counter 123, and making control signal P to L, itis also possible to fix the output of the OR gate circuit 51 to a highlevel so as to ensure that current does not flow through leakage currentdetection circuit 213 and so as to prevent erroneous operation.

According to this embodiment, application is possible to a leakagecurrent detection circuit employing a leakage current detection PchMOStransistor, and the same effects as for Embodiment 1 can be obtained,namely, detection of leakage current, comparison of the detected leakagecurrent and target current value and determination of the result aftercomparison are extremely straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed.

In the above Embodiment 1 and Embodiment 2, an odd number of stages ofcurrent mirror circuits are used, but when a current mirror circuit ofan even number of stages is used, a combination of the reference voltagegenerating circuit of Embodiment 1 and the leakage current detectioncircuit of Embodiment 2, or a combination of the reference voltagegenerating circuit of Working Example 2 and the leakage currentdetection circuit of Working Example 1 is possible.

Embodiment 3

Embodiment 3 is an example of applying a voltage amplifying circuitinstead of a current mirror circuit at a leakage current detectioncircuit employing a leakage current detection NchMOS transistor.

FIG. 4 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 3 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 4, semiconductor integrated circuit apparatus 300 is equippedwith NchMOS transistor leakage current detection block 310, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 300 adopts a basicconfiguration employing leakage current detection NchMOS transistorT_(n1) with a drain connected to a constant current source, for leakagecurrent detection of the NchMOS transistor Tn_((LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 310 is comprised of reference voltagegenerating circuit 111, voltage amplifying circuit 320, and leakagecurrent detection circuit 113. Leakage current detection block 310arbitrarily amplifies a leakage current value of leakage currentdetection NchMOS transistor T_(n1) of leakage current detection circuit113 using voltage amplifying circuit 320, and makes detection of leakagecurrent and determination straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed. Moreover, the configurationis such that current does not pass through leakage current detectioncircuit 113 when leakage current detection circuit 113 is not operating.

Voltage amplifying circuit 320 is comprised of operational amplifierOP₁, and resistors R₁ and R₂. The drain of NchMOS transistor T_(n6) ofreference voltage generating circuit 111 is connected to a + input ofoperational amplifier OP₁, a − input of operational amplifier OP₁ isconnected to low potential side supply voltage V_(SS) via resistor R₁,and is connected to the output of operational amplifier OP₁ via resistorR₂. High potential side supply voltage V_(DD) is applied as a + supplyto operational amplifier OP₁, and a supply voltage V_(SS2) that is lowerthan V_(SS) is applied as a − supply voltage. Output of operationalamplifier OP₁ is connected to the gate of leakage current detectionNchMOS transistor T_(n1). A substrate voltage control operation forsemiconductor integrated circuit apparatus 300 of the configurationdescribed above will be described below.

The relationship between drain potential V_(g2) of NchMOS transistorT_(n6) of reference voltage generating circuit 111 and gate potentialV_(g1)of leakage current detection NchMOS transistor T_(n1) is expressedin the following equation (9).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack & \; \\{V_{g\; 1} = {V_{g\; 2} \cdot \frac{R_{1} + R_{2}}{R_{1}}}} & (9)\end{matrix}$

Gate potential V_(g2) can be expressed by equation (6), and gatepotential V_(g1) can be expressed by the following equation (10).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack & \; \\{V_{g\; 1} = {{S \cdot \frac{R_{1} + R_{2}}{R_{1}} \cdot \log}\frac{W_{2}}{W_{1}}}} & (10)\end{matrix}$

Leakage current detection ratio of leakage current of NchMOS transistorT_(n (LSI)) of internal circuit 130 and leakage current detection NchMOStransistor T_(n1) can then be expressed by the following equation (11).

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack & \; \\{\frac{I_{L.{LSI}}}{I_{L.{LCM}}} = {\frac{W_{LSI}}{L_{LCM}} \cdot \left( \frac{W_{1}}{W_{2}} \right)^{\frac{R_{1} + R_{2}}{R_{1}}}}} & (11)\end{matrix}$

As can be seen from equation (11), the leakage current detection ratiohas no influence due to fluctuation in supply voltage and temperatureand process variations so that it is possible to design the leakagecurrent detection ratio by the ratio of channel width W₁ and W₂ ofNchMOS transistor T_(n6) and NchMOS transistor T_(n7) and the values ofresister R₁ and resister R₂. Further, it is possible to increase thecurrent value by an arbitrary ratio using voltage amplifying circuit320. Therefore, it is possible to increase leakage detection currentvalue according to the portion of increase in potential.

According to this embodiment, it is possible to obtain V_(g1) that isV_(g2) amplified by an arbitrary ratio even by using voltage amplifyingcircuit 320 that uses operational amplifiers instead of current mirrorcircuit 112, and the same effects as for Embodiment 1 can be obtained.

Embodiment 4

Embodiment 4 is an example of applying a voltage amplifying circuitinstead of a current mirror circuit at a leakage current detectioncircuit employing a leakage current detection PchMOS transistor.

FIG. 5 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 4 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 3 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 5, semiconductor integrated circuit apparatus 400 is equippedwith PchMOS transistor leakage current detection block 410, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 200 adopts a basicconfiguration employing leakage current detection PchMOS transistorT_(p51) with a drain connected to a constant current source for leakagecurrent detection of PchMOS transistor T_(p (LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 410 is comprised of reference voltagegenerating circuit 211, voltage amplifying circuit 420, and leakagecurrent detection circuit 213. Leakage current detection block 410arbitrarily amplifies a leakage current value of leakage currentdetection PchMOS transistor T_(p51) of leakage current detection circuit213 using voltage amplifying circuit 420, and makes detection of leakagecurrent and determination straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed. Moreover, the configurationis such that current does not pass through leakage current detectioncircuit 213 when leakage current detection circuit 213 is not operating.

Voltage amplifying circuit 420 is comprised of operational amplifier OP₁and resistors R₁ and R₂, as with voltage amplifying circuit 320 of FIG.4. The drain of PchMOS transistor T_(p56)of reference voltage generatingcircuit 211 is connected to a + input of operational amplifier OP₁, a −input of operational amplifier OP₁ is connected to high potential sidesupply voltage V_(DD) via resistor R₁, and is connected to the output ofoperational amplifier OP₁ via resistor R₂. High potential side supplyvoltage V_(DD2) that is a supply voltage higher than high potential sidesupply voltage V_(DD) is applied to operational amplifier OP₁ as a +supply, and low potential side supply V_(SS) is applied as a − supply.Output of operational amplifier OP₁ is connected to the gate of leakagecurrent detection PchMOS transistor T_(p51).

Semiconductor integrated circuit apparatus 400 of this embodimentapplies voltage amplifying circuit 420 instead of current mirror circuit212 of semiconductor integrated circuit apparatus 200 of FIG. 3, and thetheory of operation is the same as Embodiment 2 of FIG. 3. Further, theoperation of voltage amplifying circuit 420 is also exactly the same asthe substrate voltage control operation of voltage amplifying circuit320 of Embodiment 3 of FIG. 4.

It is therefore possible to obtain the same effects as for Embodiments 1to 3.

Embodiment 5

Embodiment 5 is an example of applying a separate reference potentialgenerating circuit to the reference potential generating circuit of theleakage current detection block.

FIG. 6 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 5 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 6, semiconductor integrated circuit apparatus 500 is equippedwith NchMOS transistor leakage current detection block 510, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 500 adopts a basicconfiguration employing leakage current detection NchMOS transistorT_(n1) with a drain connected to a constant current source, for leakagecurrent detection of NchMOS transistor T_(n (LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 510 is comprised of reference voltagegenerating circuit 511, current mirror circuit 112, and leakage currentdetection circuit 113. Leakage current detection block 510 arbitrarilyamplifies a leakage current value of leakage current detection NchMOStransistor T_(n1) of leakage current detection circuit 113 using currentmirror circuit 112, and makes detection of leakage current anddetermination straightforward. Further, it is possible to accelerate theresponse to substrate voltage control so that fluctuation of substratevoltage can also be suppressed. Moreover, the configuration is such thatcurrent does not pass through leakage current detection circuit 113 whenleakage current detection circuit 113 is not operating.

Reference voltage generating circuit 511 is comprised of NchMOStransistor T_(n6) and NchMOS transistor T_(n7) constituting voltagegenerating section 511 a that generates a potential for generating gatepotential V_(g1) of leakage current detection NchMOS transistor T_(n1)of leakage current detection circuit 113, NchMOS transistor T_(n5) witha source connected to low potential side supply voltage V_(SS), and adrain and gate further connected to a separate constant current source511 b, NchMOS transistor T_(n9), PchMOS transistor T_(p9), PchMOStransistor T_(p8), PchMOS transistor T_(p6), and PchMOS transistorT_(p1) of leakage current detection circuit 113 constituting constantcurrent source 511 b that supplies a constant current to this NchMOStransistor T_(n8), NchMOS transistor T_(n6) and NchMOS transistorT_(n7).

Namely, reference voltage generating circuit 511 is such that NchMOStransistor T_(n8) with a source connected to low potential side supplyvoltage V_(ss), and a drain and gate further connected to a separateconstant current source 511 b is further added to reference voltagegenerating circuit 111 of FIG. 1, the gates of NchMOS transistors T_(n6)and T_(n7) are connected in common, and are connected to the drain ofNchMOS transistor T_(n8).

In other words, a configuration is adopted where a drain voltage ofNchMOS transistor T_(n8) with the gate and drain connected to constantcurrent source 511 b and the source connected to V_(SS) is applied togate potential V_(g3) of NchMOS transistors T_(n6) and T_(n7) generatinga reference potential.

Here, the relationship of current I₆ flowing through NchMOS transistorsT_(n6) and T_(n7) and current I₇ flowing through NchMOS transistorT_(n8) are given as follows.

FIG. 24 shows the relationship between V_(g) and V_(b), and I_(b) of asemiconductor integrated circuit apparatus of the related art.

Referring to Document 2 of the related art, as shown in FIG. 24, thethreshold voltage of each NchMOS transistor is taken to be 0.55V,W₂/W₁=10, W₃=W₂, and the S parameter is taken to be 0.08V, and assumingthat V_(g3)=0.55V, V_(g2)=0.08V, then the gate-source voltage V_(gs) ofNchMOS transistor T_(n7) can be expressed by the following equation(12).

[Equation 12]

V _(gs) =V _(g3) −V _(g2)=0.55V−S  (12)

Therefore, I₆ and I₇ can be expressed by the following equation (13).

[Equation 13]

I ₇=10·I ₆  (13)

Namely, the current I₇ flowing through T_(n6) is ten times the currentI₆ flowing through T_(n6) and T_(n7.)

As with the apparatus disclosed in Document 2 as a constant currentsource, considering the case of a PchMOS transistor with a gateconnected to V_(SS) and a source connected to V_(DD), taking, forexample, I₆=1 nA, I₇=10 nA, when on resistance of a PchMOS transistor ofminimum dimensions is taken to be approximately 200 KΩ, channel width ofconstant current source PchMOS transistor T_(p6) with current I₆ flowingthrough is taken to be approximately 200 KΩ, channel length becomes 650μm, and the channel length of constant current source PchMOS transistorT_(p7) with current I₇ flowing through becomes 65 μm. In this case, itis possible to make the size of the constant current source transistorone tenth smaller.

Further, in this embodiment, the size of the circuit increases comparedto the apparatus disclosed in document 2, but by deciding the currentvalue using NchMOS transistor T_(n9), and constituting a current mirrorcircuit with NchMOS transistor T_(p9) as constant current source 511 b,it is no longer necessary to use an MOS transistor with an extremelylong channel length as described above, the increase in surface area dueto the circuit increase is only slight, and the effects of the reductionin transistor size as described above are larger. If the number ofstages of the current mirror circuit is increased, it is possible tofurther reduce the surface area.

Compared to Embodiment 1, this embodiment takes the advantage of beingable to independently control the gates of NchMOS transistors T_(n6) andT_(n7) by a separate NchMOS transistor T_(n8), and having the broadenedrange of possible current adjustment.

Other than reference voltage generating circuit 511, this embodiment isidentical to Embodiment 1, and the relationship of the detection ratiofor leakage current of NchMOS transistor T_(n (LSI)) of the internalcircuit and leakage current of leakage current detection NchMOStransistor T_(n1) shown in equation (8) is established.

Embodiment 6

Embodiment 6 is an example of applying a separate reference potentialgenerating circuit to the reference potential generating circuit of theleakage current detection block.

FIG. 7 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 6 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 3 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 7, semiconductor integrated circuit apparatus 600 is equippedwith PchMOS transistor leakage current detection block 610, substratevoltage control block 120 controlling substrate voltage control, andinternal circuit 130 having a plurality of MOS transistors on asemiconductor substrate. Semiconductor integrated circuit apparatus 600adopts a basic configuration employing leakage current detection PchMOStransistor T_(p51) with a drain connected to a constant current source,for leakage current detection of PchMOS transistor T_(p (LSI))equivalently representing internal circuit 130.

Leakage current detection block 610 is comprised of reference voltagegenerating circuit 611, current mirror circuit 212, and leakage currentdetection circuit 213. Leakage current detection block 610 arbitrarilyamplifies a leakage current value of leakage current detection PchMOStransistor T₉₅₁ of leakage current detection circuit 213 using currentmirror circuit 212, and makes detection of leakage current anddetermination straightforward. Further, it is possible to accelerate theresponse to substrate voltage control so that fluctuation of substratevoltage can also be suppressed. Moreover, the configuration is such thatcurrent does not pass through leakage current detection circuit 213 whenleakage current detection circuit 213 is not operating.

Reference voltage generating circuit 611 is comprised of PchMOStransistor T_(p56) and PchMOS transistor T_(p57) constituting voltagegenerating section 611 a that generates a potential for generating gatepotential V_(g11) of leakage current detection PchMOS transistor T_(p51)of leakage current detection circuit 213, PchMOS transistor T_(p58) witha source connected to high potential side supply voltage V_(DD), and adrain and gate further connected to a separate constant current source611 b, PchMOS transistor T_(p59), NchMOS transistor T_(n59), NchMOStransistor T_(n58) NchMOS transistor T_(n56), and NchMOS transistorT_(n51) of leakage current detection circuit 213 constituting constantcurrent source Glib that supplies a constant current to this PchMOStransistor T_(p58), PchMOS transistor T_(p56) and PchMOS transistorT_(p57).

Namely, reference voltage generating circuit 611 is such that PchMOStransistor T_(p58) with a source connected to high potential side supplyvoltage V_(DD) and a drain and gate further connected to a separateconstant current source 611 b is further added to reference voltagegenerating circuit 211 of FIG. 3, the gates of NchMOS transistorsT_(p56) and T_(p57) are connected in common, and are connected to thedrain of PchMOS transistor T_(p58).

In other words, a configuration is adopted where a drain voltage ofPchMOS transistor T_(p58) with the gate and drain connected to constantcurrent source 611 b, and the source connected to V_(DD) is applied togate potential V_(g13) of PchMOS transistors T_(p56) and T_(p57)generating a reference potential.

According to Embodiment 6, the theory of operation is exactly the sameas for the circuit shown in FIG. 6 simply with NchMOS transistorschanged for PchMOS transistors, and vice versa.

It is therefore possible to obtain the same effects as for Embodiments 1to 5. In particular, compared to Embodiment 2, this embodiment takes theadvantage of being able to independently control the gates of PchMOStransistors T_(p56) and T_(p57) using a separate PchMOS transistorT_(p58), and having the broadened range of possible current adjustment,as with Embodiment 5.

Embodiment 7

Embodiment 7 is an example of applying a voltage amplifying circuitinstead of the current mirror circuit and also applying a separatereference potential generating circuit at the reference potentialgenerating circuit of the leakage current detection block at the leakagecurrent detection circuit employing the leakage current detection NchMOStransistor.

FIG. 8 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 7 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 4 and FIG. 6 are assigned the samenumerals and description for the overlapped portions will be omitted.

In FIG. 8, semiconductor integrated circuit apparatus 700 is equippedwith NchMOS transistor leakage current detection block 710, substratevoltage control block 120 controlling substrate voltage control, andinternal circuit 130 having a plurality of MOS transistors on asemiconductor substrate. Semiconductor integrated circuit apparatus 700adopts a basic configuration employing leakage current detection NchMOStransistor T_(n1) with a drain connected to a constant current source,for leakage current detection of NchMOS transistor T_(n (LSI))equivalently representing internal circuit 130.

Leakage current detection block 710 is comprised of reference voltagegenerating circuit 511, voltage amplifying circuit 320, and leakagecurrent detection circuit 113. Leakage current detection block 710arbitrarily amplifies a leakage current value of leakage currentdetection NchMOS transistor T_(n1) of leakage current detection circuit113 using voltage amplifying circuit 320, and makes detection of leakagecurrent and determination straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed. Moreover, the configurationis such that current does not pass through leakage current detectioncircuit 113 when leakage current detection circuit 113 is not operating.

Reference voltage generating circuit 511 is such that NchMOS transistorT_(n8) with a source connected to low potential side supply voltageV_(ss) and a drain and gate further connected to a separate constantcurrent source 511 b is further added to reference voltage generatingcircuit 111 of FIG. 4, the gates of NchMOS transistors T_(n6) and T_(n7)are connected in common, and are connected to the drain of NchMOStransistor T_(n8).

As with FIG. 4, voltage amplifying circuit 320 is comprised ofoperational amplifier OP₁, and resistors R₁ and R₂. The drain of NchMOStransistor T_(n6) of reference voltage generating circuit 511 isconnected to a + input of operational amplifier OP₁, a − input ofoperational amplifier OP₁ is connected to low potential side supplyvoltage V_(SS) via resistor R₁, and is connected to the output ofoperational amplifier OP₁ via resistor R₂. High potential side supplyvoltage V_(DD) is applied as a +.supply to operational amplifier OP₁,and a supply voltage V_(SS2) that is lower than V_(SS) is applied as a −supply voltage. Output of operational amplifier OP₁ is connected to thegate of leakage current detection NchMOS transistor T_(n1).

According to this embodiment, other than reference voltage generatingsection 511, this embodiment is identical to Embodiment 3 of FIG. 4, andthe relationship of the detection ratio for leakage current of NchMOStransistor T_(n (LSI)) of the internal circuit and leakage current ofleakage current detection NchMOS transistor T_(n1) shown in equation(11) is established.

Further, reference voltage generating circuit 511 is provided.Therefore, compared to Embodiment 1, this embodiment takes the advantageof being able to independently control the gates of NchMOS transistorsT_(n6) and T_(n7) using a separate NchMOS transistor T_(n8), and havingthe broadened range of possible current adjustment, as with Embodiment6.

Embodiment 8

Embodiment 8 is an example of applying a voltage amplifying circuitinstead of the current mirror circuit and also applying a separatereference potential generating circuit at the reference potentialgenerating circuit of the leakage current detection block at the leakagecurrent detection circuit employing the leakage current detection PchMOStransistor.

FIG. 9 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 8 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 5 and FIG. 7 are given the samenumerals and description for the overlapped portions will be omitted.

In FIG. 9, semiconductor integrated circuit apparatus 800 is equippedwith PchMOS transistor leakage current detection block 810, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 800 adopts a basicconfiguration employing leakage current detection PchMOS transistorT_(p51) with a drain connected to a constant current source, for leakagecurrent detection of PchMOS transistor T_(p (LSI)) equivalentlyrepresenting internal circuit 130.

Leakage current detection block 810 is comprised of reference voltagegenerating circuit 611, voltage amplifying circuit 420, and leakagecurrent detection circuit 213. Leakage current detection block 810arbitrarily amplifies a leakage current value of leakage currentdetection PchMOS transistor T_(p51) of leakage current detection circuit213 using voltage amplifying circuit 420, and makes detection of leakagecurrent and determination straightforward. Further, it is possible toaccelerate the response to substrate voltage control so that fluctuationof substrate voltage can also be suppressed. Moreover, the configurationis such that current does not pass through leakage current detectioncircuit 213 when leakage current detection circuit 213 is not operating.

Reference voltage generating circuit 611 is such that PchMOS transistorT_(p59) with a source connected to high potential side supply voltageV_(DD) and a drain and gate further connected to a separate constantcurrent source 611 b is further added to reference voltage generatingcircuit 211 of FIG. 5, the gates of PchMOS transistors T_(p56) andT_(p57) are connected in common, and are connected to the drain ofPchMOS transistor T_(p58).

As with FIG. 5, voltage amplifying circuit 420 is comprised ofoperational amplifier OP₁, and resistors R₁ and R₂. The drain of PchMOStransistor T_(p56) of reference voltage generating circuit 611 isconnected to a + input of operational amplifier OP₁, a − input ofoperational amplifier OP₁ is connected to high potential side supplyvoltage V_(DD) via resistor R₁, and is connected to the output ofoperational amplifier OP₁ via resistor R₂. High potential side supplyvoltage V_(DD2) that is a supply voltage higher than high potential sidesupply voltage V_(DD) is applied to operational amplifier OP₁ as a +supply, and low potential side supply V₅₉ is applied as a − supply.Output of operational amplifier OP₁ is connected to the gate of leakagecurrent detection PchMOS transistor T₉₅₁.

In this embodiment, the theory of operation is exactly the same as thecircuit shown in FIG. 8 simply with NchMOS transistors changed forPchMOS transistors, and vice versa. According to this embodiment, inaddition to the effects of Embodiments 1 to 4, this embodiment takes theadvantage of being able to independently control the gates of PchMOStransistors T_(p56) and T_(p57) using a separate PchMOS transistorT_(p58) and the broadened range of possible current adjustment.

Embodiment 9

Embodiment 9 shows an example of applying a separate leakage currentdetection circuit and reference potential generating circuit to theleakage current detection circuit and reference potential generatingcircuit of the leakage current detection block.

FIG. 10 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 9 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 10, semiconductor integrated circuit apparatus 900 is equippedwith NchMOS transistor leakage current detection block 910, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 900 adopts a basicconfiguration employing a source follower circuit constructed usingleakage current detection NchMOS transistor T_(n21) with a drainconnected to high potential side supply voltage V_(DD), a sourceconnected to a constant current source, and a substrate voltagecontrolled by substrate voltage control block 120, for NchMOS transistorT_(n (LSI)) equivalently representing internal circuit 130.

Leakage current detection block 910 is comprised of reference voltagegenerating circuit 911, current mirror circuit 112, and leakage currentdetection circuit 913. Leakage current detection block 910 arbitrarilyamplifies the leakage current value of leakage current detection NchMOStransistor T_(n21) of leakage current detection circuit 913 usingcurrent mirror circuit 112, detects source potential of leakage currentdetection NchMOS transistor T_(n21) by potential comparison with areference potential using a source follower circuit constructed fromleakage current detection NchMOS transistor T_(n21), and makes detectionof leakage current and determination straightforward. Further, theconfiguration is such that current does not pass through leakage currentdetection circuit 913 when leakage current detection circuit 913 is notoperating.

Reference voltage generating circuit 911 is comprised of NchMOStransistor T_(n6) and NchMOS transistor T_(n7) constituting voltagegenerating section 911 a that generates potential for generating gatepotential V_(g1) of leakage current detection NchMOS transistor T_(n21)of leakage current detection circuit 913, NchMOS transistor T_(n9),PchMOS transistor T_(p9) and PchMOS transistor T_(p6) constitutingconstant current source 911 b that supplies a constant current to NchMOStransistor T_(n6) and NchMOS transistor T_(n7), and NchMOS transistorT_(n10) and PchMOS transistor T_(p10) constituting circuit 911 c thatgenerates a gate voltage for constant current source NchMOS transistorT_(n22) of leakage current detection circuit 913.

Namely, reference voltage generating circuit 911 is further providedwith NchMOS transistor T_(n10) with a source connected to low potentialside supply voltage V_(SS2) of a lower potential than low potential sidesupply voltage V_(ss) and a drain and gate connected to the gate ofconstant current source NchMOS transistor T_(n22) of leakage currentdetection circuit 913 and PchMOS transistor T_(p10) supplying a constantcurrent to NchMOS transistor T_(n10), at reference voltage generatingcircuit 111 of FIG. 1.

Leakage current detection circuit 913 is comprised of leakage currentdetection NchMOS transistor T_(n21) with a drain connected to V_(DD), asource connected to a constant current source, potential V_(g1) receivedat a gate, and substrate voltage controlled by substrate voltage controlblock 120, constant current source NchMOS transistor T_(n22) with asource connected to low potential side supply voltage V_(ss2) of apotential lower than the low potential side supply voltage V_(ss) and adrain connected to leakage current detection NchMOS transistor T_(n21)comparator COMP1 comparing source potential of leakage current detectionNchMOS transistor T_(n21) and V_(SS) potential that is a referencepotential, and PchMOS transistor T_(p11) with a source connected to highpotential side supply voltage V_(DD), a drain connected to comparatorCOMP1, and control signal N from controller 121 received at a gate viainverter circuit G3.

In this way, instead of leakage current detection NchMOS transistorT_(n1) connected to the circuit as in each of Embodiments 1, 3, 5 and 7described above, leakage current detection block 910 adopts aconfiguration using a source follower circuit configured from leakagecurrent detection NchMOS transistor T_(n21) with a drain connected toV_(DD), a source connected to a constant current source, and substratevoltage controlled by substrate voltage control block 120, and comparingthe source potential of leakage current detection NchMOS transistorT_(n21) with V_(SS) that is a reference potential by comparator COMP1.

A substrate voltage control operation for semiconductor integratedcircuit apparatus 900 of the configuration described above will bedescribed below. The overall operation is the same as Embodiments 1 and3, so descriptions thereof will be omitted. Only different aspects ofthe operation will be described.

The configuration for the leakage current detection circuit differs fromthat of Embodiment 1 shown in FIG. 1 in that, rather than connecting theconstant current source to the drain side of leakage current detectionNchMOS transistor T_(n21), this embodiment adopts a configuration wherethe constant current source is connected to the source side of leakagecurrent detection NchMOS transistor T_(n21), and this source potentialis compared with V_(SS) that is the reference potential using comparatorCOMP'. As a power supply voltage, V_(SS2) that is a voltage lower thanV_(DD) and V_(SS) is applied to comparator COMP1. At internal circuit130, V_(SS) is connected to a plurality of NchMOS transistor sources.Output of comparator COMP1 is inputted to substrate voltage controlblock 120.

Comparator COMP1 is comprised of a comparator and operational amplifier,and if the source potential of leakage current detection NchMOStransistor T_(n21) is higher than the reference potential V_(SS),detection signal N with low level is outputted. Substrate voltagecontrol block 120 carries out the same operation as Embodiment 1 in thatthe substrate voltage is outputted, and the substrate voltage of leakagecurrent detection NchMOS transistor T_(n22) is lowered (deepens). As aresult, the threshold voltage of leakage current detection NchMOStransistor T_(n21) becomes large, and source potential is lowered.Conversely, if the source potential is lower than the reference voltageV_(SS), comparator COMP1 outputs a detection signal N with high leveland substrate voltage control block 120 operates in such a manner toraise (make shallow) the substrate voltage of leakage current detectionNchMOS transistor T_(n21). As a result, the threshold voltage of leakagecurrent detection NchMOS transistor T_(n21) becomes small, and sourcepotential is raised.

As in Embodiment 1, a circuit generating gate potential of leakagecurrent detection NchMOS transistor T_(n21) is comprised of referencevoltage generating circuit 911 and current mirror circuit 112. However,circuit of NchMOS transistor T_(n10) and PchMOS transistor T_(p10)generating a gate voltage for constant current source NchMOS transistorT_(n22) is added to reference voltage generating circuit 911. Therelationship between the detection ratio for the leakage current of theNchMOS transistor of the internal circuit and the leakage current of theleakage current detection NchMOS transistor shown in equation (8) isalso satisfied.

As described above, according to this embodiment, instead of leakagecurrent detection NchMOS transistor T_(n1), a source follower circuitconfigured from NchMOS transistor T_(n21) with a drain connected to ahigh potential side supply voltage V_(DD), a source connected to aconstant current source, and substrate voltage controlled by substratevoltage control block 120 is used, and the source potential of leakagecurrent detection NchMOS transistor T_(n21) is compared with lowpotential side supply voltage V_(SS) that is a reference potential bycomparator COMP1. As a result, the leakage current can then be similarlydetected. In particular, as it is possible to increase the detectioncurrent value of leakage current detection NchMOS transistor T_(n21) byan arbitrary ratio, detection of leakage current, comparison of thedetected leakage current and target current value and determination ofthe result after comparison are extremely straightforward.

Embodiment 10

Embodiment 10 is an example of applying a separate leakage currentdetection circuit and reference potential generating circuit to theleakage current detection circuit and reference potential generatingcircuit of the leakage current detection block.

FIG. 11 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 10 of the present invention. Thisembodiment shows an example applied to, semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 3 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 11, semiconductor integrated circuit apparatus 1000 is equippedwith PchMOS transistor leakage current detection block 1010, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1000 adopts abasic configuration employing a source follower circuit constructedusing leakage current detection PchMIS transistor T_(p71) with a drainconnected to low potential side supply voltage V_(SS), a sourceconnected to a constant current source, and a substrate voltagecontrolled by substrate voltage control block 120, for PchMOS transistorT_(p (LSI)) equivalently representing internal circuit 130.

Leakage current detection block 1010 is comprised of reference voltagegenerating circuit 1011, current mirror circuit 212, and leakage currentdetection circuit 1013. Leakage current detection block 1010 arbitrarilyamplifies the leakage current value of leakage current detection PchMOStransistor T_(p71) of leakage current detection circuit 1013 usingcurrent mirror circuit 212, detects source potential of leakage currentdetection PchMOS transistor T_(p71) by potential comparison with areference potential using a source follower circuit constructed fromleakage current detection PchMOS transistor T_(p71), and makes detectionof leakage current and determination straightforward. Further, theconfiguration is such that current does not pass through leakage currentdetection circuit 1013 when leakage current detection circuit 1013 isnot operating.

Reference voltage generating circuit 1011 is comprised of PchMOStransistor T_(p56) and PchMOS transistor T_(p57) constituting voltagegenerating section 1011 a that generates potential for generating gatepotential V_(g11) of leakage current detection PchMOS transistor T_(p71)of leakage current detection circuit 1013, PchMOS transistor T_(p59),NchMOS transistor T_(n59) and NchMOS transistor T_(n56) constitutingconstant current source 1011 b that supplies a constant current toPchMOS transistor T_(p56) and PchMOS transistor T_(p57), and PchMOStransistor T_(p60) and NchMOS transistor T_(n60) constituting circuit1011 c that generates a gate voltage for constant current source PchMOStransistor T_(p72) of leakage current detection circuit 1013.

Namely, reference voltage generating circuit 1011 is further providedwith PchMOS transistor T_(p60) with a source connected to high potentialside supply voltage V_(DD2) of a higher potential than high potentialside supply voltage V_(DD) and a drain and gate connected to the gate ofconstant current source PchMOS transistor T_(p72) of leakage currentdetection circuit 1013 and NchMOS transistor T_(n60) supplying aconstant current to PchMOS transistor T_(p60), at reference voltagegenerating circuit 211 of FIG. 3.

Leakage current detection circuit 1013 is comprised of leakage currentdetection PchMOS transistor T_(p71) with a drain connected to V_(SS), asource connected to a constant current source, potential V_(g11)received at a gate, and substrate voltage controlled by substratevoltage control block 120, constant current source PchMOS transistorT_(p72) with a source connected to high potential side supply voltageV_(DD2) of a potential higher than the high potential side supplyvoltage V_(DD) and a drain connected to leakage current detection PchMOStransistor T_(p71), comparator COMP2 comparing source potential ofleakage current detection PchMOS transistor T_(p71) and V_(DD) potentialthat is a reference potential, and NchMOS transistor T_(n61) with asource connected to low potential side supply voltage V_(ss), a drainconnected to comparator COMP2, and control signal P from controller 121received at a gate via inverter circuit G52.

In this way, instead of the leakage current detection PchMOS transistorT_(p51) connected to the circuit as in each of Embodiments 2, 4, 6 and 8described above, leakage current detection block 1010 adopts aconfiguration using a source follower circuit configured from leakagecurrent detection PchMOS transistor T_(p71) with a drain connected toV_(ss), a source connected to a constant current source, and substratevoltage controlled by substrate voltage control block 120, and comparingthe source potential of leakage current detection PchMOS transistorT_(p71) with V_(DD) that is a reference potential by comparator COMP2.

In this embodiment, the theory of operation is exactly the same as forthe circuit shown in FIG. 10 simply with NchMOS transistors changed forPchMOS transistors, and vice versa. Therefore, in this embodiment 10, asin Embodiment 9, as it is possible to increase the detection currentvalue of leakage current detection PchMOS transistor T_(p71) by anarbitrary ratio, detection of leakage current, comparison of thedetected leakage current and target current value and determination ofthe result after comparison are extremely straightforward.

Embodiment 9 and Embodiment 10 described above are examples applied tothreshold voltage control circuits employing source follower circuitsand comparators. A configuration employing a source follower circuit anda comparator is also capable of being applied to a configuration that isa combination of voltage amplifying circuits employing operationalamplifiers shown in Embodiment 3 and Embodiment 4 of FIG. 4 and FIG. 5,and the reference voltage generating circuits shown in Embodiment 5 toEmbodiment 8 of FIG. 6 to FIG. 9, and the same effects can be obtained.

Embodiment 11

Embodiment 11 is an example applied to a leakage current detectioncircuit canceling DC offset of a comparator.

FIG. 12 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 11 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 10 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 12, semiconductor integrated circuit apparatus 1100 is equippedwith NchMOS transistor leakage current detection block 1110, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1100 then adopts abasic configuration employing a source follower circuit constructedusing leakage current detection NchMOS transistor T_(n21) with a drainconnected to high potential side supply voltage V_(DD), a sourceconnected to a constant current source, and a substrate voltagecontrolled by substrate voltage control block 1120, for NchMOStransistor Tn_((LSI)) equivalently representing internal circuit 130.

Leakage current detection block 1110 is comprised of reference voltagegenerating circuit 911, current mirror circuit 112, and leakage currentdetection circuit 1113. Leakage current detection block 1110 arbitrarilyamplifies the leakage current value of leakage current detection NchMOStransistor T_(n21) of leakage current detection circuit 1113 usingcurrent mirror circuit 112, detects source potential of leakage currentdetection NchMOS transistor T_(n21) by potential comparison with areference potential using a source follower circuit constructed fromleakage current detection NchMOS transistor T_(n21), and makes detectionof leakage current and determination straightforward. Further, theconfiguration is such that current does not pass through leakage currentdetection circuit 1113 when leakage current detection circuit 1113 isnot operating.

Leakage current detection circuit 1113 is comprised of leakage currentdetection NchMOS transistor T_(n21) with a drain connected to V_(DD), asource connected to a constant current source, potential V_(g1) receivedat a gate, and substrate voltage controlled by substrate voltage controlblock 1120, constant current source NchMOS transistor T_(n22) with asource connected to low potential side supply voltage V_(ss2) of a lowerpotential than low potential side supply voltage V_(ss), and a drainconnected to leakage current detection NchMOS transistor T_(n21),comparator COMP1 comparing source potential of leakage current detectionNchMOS transistor T_(n21) and V_(SS) potential that is the referencepotential, input switching switch 1114 that is arranged between therespective input terminals IN1, IN2 of comparator COMP1 and the sourceof leakage current detection NchMOS transistor T_(n21) and the V_(SS)terminal, and switches between the source of leakage current detectionNchMOS transistor T_(n21) and the V_(SS) terminal and the respectiveinput terminals of comparator COMP1, and PchMOS transistor T_(p11) witha source connected to high potential side supply voltage V_(DD), a drainconnected to comparator COMP1, and control signal N from controller 1121received at a gate via inverter circuit G4.

Namely, leakage current detection circuit 1113 adopts a configurationwhere input switching switch 1114 arranged between input terminals IN1,IN2 of comparator COMP1 and the source of leakage current detection NchMOS transistor T_(n21) and V_(SS) terminal, and the source of leakagecurrent detection Nch MOS transistor T_(n21) and V_(SS) terminal and therespective input terminals of comparator COMP1 switched between wheninternal circuit 130 is not operating is provided between the source ofleakage current detection Nch MOS transistor T_(n21) of leakage currentdetection circuit 913 and comparator COMP1 of FIG. 10.

Substrate voltage control block 1120 is comprised of controller 1121receiving the output of comparator COMP1 and controlling to change asubstrate voltage applied to substrates of leakage current detectionNchMOS transistor T_(n21) and NchMOS transistors T_(n (LSI)) of internalcircuit 130, and DA converter 122 DA converting a digital value fromcontroller 1121 and generating a substrate voltage. Further, substratevoltage control block 1120 is configured from a digital circuit for easeof switching control of input switching switch 1114 and offsetadjustment amount operation control.

In this embodiment, at semiconductor integrated circuit apparatus 900 ofFIG. 10, input switching switch 1114 is provided between the respectiveinput terminals IN1, IN2 of comparator COMP1 and the source of NchMOStransistor T_(n21) and the V_(SS) terminal. Further, controller 1121 ofsubstrate voltage control block 1120 is further equipped with functionsfor controlling switching of input switching switch 1114 and controllingoffset adjustment amount operations.

FIG. 13 shows a circuit configuration for controller 1121.

In FIG. 13, controller 1121 is comprised of polarity inverter 1133comprised of inverter 1131 and selector 1132 selectively inverting thepolarity of the output signal of comparator COMP1, input data correctionsection 1134, selector 1135 switching register 2 and register 13, andcontrol circuit 1136 controlling each circuit in such a manner as toinput an operation mode signal, and output mode switching signal 1, modeswitching signal 2, and control signal N/P.

Input switching switch 1114 and polarity inverter 1133 are controlled bymode switching signal 1, and selector 1135 is controlled by modeswitching signal 2.

Input data correction section 1134 is comprised of substrate voltagesetting value generating section 1143 composed of up-down counter 1141and register 1142 (register 1) employing a method of successivecomparison where one LSB (least significant bit) is changed at a time,substrate voltage setting value upper limit-lower limit comparatorcircuit 1148 composed of substrate voltage setting upper limit valueregister 1144, substrate voltage setting lower limit value register1145, comparator circuit 1146 and register 1147 (register 2), register1149 (register 11) and register 1150 (register 12) temporarily storing afirst substrate voltage setting value and second substrate voltagesetting value, operation circuit 1151, and register 1152 (register 13)storing operation results.

The operation of semiconductor integrated circuit apparatus 1100 of theconfiguration described above will be described below.

A circuit generating gate potential V_(g1)of leakage current detectionNchMOS transistor T_(n21) is exactly the same as Embodiment 9 of FIG.10. The relationship between the detection ratio for the leakage currentof the NchMOS transistor of the internal circuit 130 and the leakagecurrent of NchMOS transistor T_(n21) shown in equation (8) is alsosatisfied.

The overall operation of substrate voltage control of semiconductorintegrated circuit apparatus 1100 is the same as Embodiment 9 anddescription thereof will be omitted. An offset compensation operationwill be described.

First, the operation for compensating DC offset of comparator COMP1occurring at the substrate voltage control operation will be described.

This operation is carried out by an operation (first input mode)obtaining a first substrate voltage setting value, an operation (secondinput mode) obtaining a second substrate voltage setting value, and anoperation (operation mode) obtaining a third substrate voltage settingvalue when internal circuit 130 is not operating.

It is then possible to eliminate DC offset of comparator COMP1 byapplying the substrate voltage using the third substrate voltage settingvalue obtained in this manner.

As shown in FIG. 13, input switching switch 1114 has a function forselectively connecting input terminals A and B to either of outputterminals C and D.

At the time of the first input mode, input switching switch 1114 is suchthat A terminal and C terminal are connected, and B terminal and Dterminal are connected, And selector 1132 of polarity inverter 1133allows the output signal of comparator COMP1 to pass as is.

The output signal of comparator COMP1 is then provided to up-downcounter 1141 functioning as substrate voltage setting value generatingsection 1143.

First, before starting the substrate voltage control operation, a countvalue of up-down counter 1141 and the value of register 1142 (register1) are reset to zero (0) or are set to the value measured the previoustime. Next, up-down counter 1141 counts up when the output signal ofcomparator COMP1 provided at this time is +1 (high level) and countsdown when −1 (low level), and stores this count value in register 1.

A substrate voltage setting upper limit value and a substrate voltagesetting lower limit value stored in input data correction section 1134and the value of register 1 are compared using a comparator circuit. Inthe event that the value of register 1 exceeds the substrate voltagesetting upper limit, this substrate voltage setting upper limit value isoutputted. In the event that the value of register 1 exceeds thesubstrate voltage setting lower limit value, this substrate voltagesetting lower limit value is outputted. If the value of register 1 isbetween the substrate voltage setting lower limit value and thesubstrate voltage setting upper limit value, the value of register 1 isoutputted. The outputted comparison results are then stored in register1147 (register 2).

The value of register 2 is then inputted to DA converter 122 from inputdata correction section 1134 via selector 1135 using mode switchingsignal 2. As a result, a substrate voltage corresponding to register 2from DA converter 122 is applied to the substrate of leakage currentdetection NchMOS transistor T_(n21) and the substrate of the NchMOStransistors of internal circuit 130.

Namely, if source potential of leakage current detection NchMOStransistor T_(n21) is higher than V_(SS) that is the referencepotential, comparator COMP1 outputs −1 (low level), up-down countercounts down, and the count value is stored in register 1. Comparatorcircuit 1146 compares whether or not the value of register 1 exceeds thesubstrate voltage setting upper limit value or lower limit value, andstores the results of the comparison in register 2. DA converter 122then outputs a substrate voltage corresponding to the value of register2, and lowers (deepens) the substrate voltage of leakage currentdetection NchMOS transistor T_(n21). As a result, the threshold voltageof leakage current detection NchMOS transistor T_(n21) becomes large,and source potential of NchMOS transistor T_(n21) is lowered.

Conversely, if source potential of leakage current detection NchMOStransistor T_(n21) is lower than V_(SS) that is the reference potential,comparator COMP1 outputs +1 (high level), up-down counter 1141 countsup, and the count value is stored in register 1. Comparator circuit 1146compares whether or not the value of register 1 exceeds the substratevoltage setting upper limit value or lower limit value, and stores theresults of the comparison in register 2. DA converter 122 then outputs asubstrate voltage corresponding to the value of register 2, and raises(makes shallow) the substrate voltage of leakage current detectionNchMOS transistor T_(n21). As a result, the threshold voltage of leakagecurrent detect ion NchMOS transistor T_(n21) becomes small, and sourcepotential of NchMOS transistor T_(n21) is raised.

In the following, the above loop is gone through and the same operationis carried out. This operation continues until the polarity of theoutput signal of comparator COMP1 is inverted.

Namely, upon detecting inversion of the polarity of the output signal ofcomparator COMP1, substrate voltage setting value generating section1143 holds the count value (that is the first substrate voltage settingvalue) at this time in register 1142 (register 11).

It should be noted that carrying out detection of inversion of polarityrequires consideration for slight swings in signal voltage.

Next, input switching switch 1114 is controlled, A terminal is connectedto D terminal, B terminal is connected to C terminal, and the secondinput mode is adopted.

At this time, selector 1132 of polarity inverter 1133 selects the outputsignal of inverter 1131. Namely, a signal that is the output signal ofcomparator COMP1 with the polarity inverted is provided to up-downcounter 1141.

In this state, the count value of up-down counter 1141 of substratevoltage setting value generating section 1143 returns to zero (0) andthe same operation as for the first input mode is carried out, or anoperation is carried out to obtain the second substrate voltage settingvalue by continuing from the same count value as for the first substratevoltage setting value obtained in the first input mode. The secondsubstrate voltage setting value obtained as a result is then stored inregister 1150 (register 12).

First and second substrate voltage setting values are then extractedfrom register 11 and register 12, the third substrate voltage settingvalue is calculated by taking an average value using operation circuit1151, and this is stored in register 1152 (register 13).

This third substrate voltage setting value is the substrate voltagesetting value (i.e. the substrate voltage setting value when the DCoffset of comparator COMP1 is completely cancelled) in the event thatthere is no DC offset whatsoever at comparator COMP1.

Therefore, at the time of normal operation of internal circuit 130, itis possible to completely cancel the DC offset of comparator COMP1 bycontrolling the selector using mode switching signal 2 and controllingsubstrate voltage of internal circuit 130 using the third substratevoltage setting value of register 13, and improve the precision ofcontrolling substrate voltage substantially.

According to this embodiment, input switching switch 1114 is providedbetween the respective input terminals IN1, IN2 of comparator COMP1 andthe source of NchMOS transistor T_(n21) and the V_(SS) terminal. By thenswitching between the source of NchMOS transistor T_(n21) and the V_(SS)terminal and the respective input terminals of comparator COMP1 usinginput switching switch 1114, substrate voltage adjustment is carried outtwo times, and respective substrate voltage setting values are stored inregister 1 and register 2 within controller 1121. The average of thesesubstrate voltage setting values is then taken and stored in register 3.The substrate voltage of the internal circuit is then controlled usingthe substrate voltage setting value of register 3 at the time of normaloperation of internal circuit 130. It is therefore possible tocompletely cancel DC offset errors of comparator COMP1 and improve theprecision of controlling the substrate voltage. In this way, it ispossible to detect leakage current more precisely.

Embodiment 12

Embodiment 12 is an example of applying canceling of DC offset of acomparator to a leakage current detection circuit employing a leakagecurrent detection PchMOS transistor to cancel DC offset of a comparator.

FIG. 14 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 12 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 11 to FIG. 13 are assigned thesame numerals and description for the overlapped portions will beomitted.

In FIG. 14, semiconductor integrated circuit apparatus 1200 is equippedwith PchMOS transistor leakage current detection block 1210, substratevoltage control block 1120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1200 then adopts abasic configuration employing a source follower circuit constructedusing leakage current detection PchMOS transistor T_(p71) with a drainconnected to low potential side supply voltage V_(SS), a sourceconnected to a constant current source, and a substrate voltagecontrolled by substrate voltage control block 1120, for PchMOStransistor T_(p (LSI)) equivalently representing internal circuit 130.

Leakage current detection block 1210 is comprised of reference voltagegenerating circuit 1011, current mirror circuit 212, and leakage currentdetection circuit 1213. Leakage current detection block 1210 arbitrarilyamplifies the leakage current value of leakage current detection PchMOStransistor T_(p71) of leakage current detection circuit 1213 usingcurrent mirror circuit 212, detects source potential of leakage currentdetection PchMOS transistor T_(p71) by potential comparison with areference potential using a source follower circuit constructed fromleakage current detection PchMOS transistor T_(p71), makes detection ofleakage current and determination straightforward. Further, theconfiguration is such that current does not pass through leakage currentdetection circuit 1213 when leakage current detection circuit 1213 isnot operating.

Leakage current detection circuit 1213 is comprised of leakage currentdetection PchMOS transistor T_(p71) with a drain connected to lowvoltage side supply voltage V_(ss), a source connected to a constantcurrent source, potential V_(g11) received at a gate, and substratevoltage controlled by substrate voltage control block 1120, constantcurrent source PchMOS transistor T_(p72) with a source connected to highpotential side supply voltage V_(DD2) of a potential higher than highpotential side supply voltage V_(DD), and a drain connected to leakagecurrent detection PchMOS transistor T_(p71), comparator COMP2 comparingsource potential of leakage current detection PchMOS transistor T_(p71)and V_(DD) potential that is the reference potential, input switchingswitch 1114 that is arranged between the respective input terminals IN1,IN2 of comparator COMP2 and the source of leakage current detectionPchMOS transistor T_(p71) and the V_(DD) terminal, and switches betweenthe source of leakage current detection PchMOS transistor T_(p71) andthe V_(DD) terminal and the respective input terminals of comparatorCOMP2, and NchMOS transistor T_(n61) with a source connected to lowpotential side supply voltage V_(ss), a drain connected to comparatorCOMP2, and control signal P from controller 1121 received at a gate viainverter circuit G53.

Namely, leakage current detection circuit 1213 adopts a configurationwhere input switching switch 1114 arranged between input terminals In1,IN2 of comparator COMP2 and the source of leakage current detectionPchMOS transistor T_(p71) and V_(DD) terminal and switches the source ofleakage current detection PchMOS transistor T_(p71) and V_(DD) terminaland the respective input terminals of comparator COMP2 when internalcircuit 130 is not operating is provided between the source of leakagecurrent detection PchMOS transistor T_(p71) of leakage current detectioncircuit 1013 of FIG. 11 and comparator COMP2. The circuit configurationof the above input switching switch 1114 is the same as FIG. 13.

In this embodiment, the theory of operation is exactly the same as forthe circuit shown in FIG. 12 simply with NchMOS transistors changed forPchMOS transistors, and vice versa. Namely, the same offset compensationoperation as the operation described in FIG. 12 and FIG. 13 is added inthe basic operation of Embodiment 10 of FIG. 11

Therefore, in this embodiment 12 also and as in Embodiment 10, as it ispossible to increase the detection current value of leakage currentdetection PchMOS transistor T_(p71) by an arbitrary ratio, detection ofleakage current, comparison of the detected leakage current and targetcurrent value and determination of the result after comparison areextremely straightforward. In addition to this effect, as withEmbodiment 11, it is therefore possible to completely cancel the DCoffset of comparator COMP2, and improve the precision of controlling thesubstrate voltage substantially.

Embodiment 13

Embodiment 13 is an example of applying a separate leakage currentdetection circuit to the leakage current detection circuit of theleakage current detection block.

FIG. 15 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 13 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 and FIG. 10 are assigned thesame numerals and description for the overlapped portions will beomitted.

In FIG. 15, semiconductor integrated circuit apparatus 1300 is equippedwith NchMOS transistor leakage current detection block 1310, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1300 adopts abasic configuration carrying out potential comparison of drain potentialof leakage current detection NchMOS transistor T_(n31) with a sourceconnected to V_(SS), the gate and drain connected together and connectedto a constant current source and a substrate voltage controlled bysubstrate voltage control block 120, for NchMOS transistor T_(n (LSI))equivalently representing internal circuit 130, and voltage amplifieroutput potential due to current mirror circuit 112 by a comparator.

Leakage current detection block 1310 is comprised of reference voltagegenerating circuit 111, current mirror circuit 112, and leakage currentdetection circuit 1313.

Leakage current detection circuit 1313 is comprised of constant currentsource PchMOS transistor T_(p31) with a source connected to highpotential side supply voltage V_(DD) and a drain connected to leakagecurrent detection NchMOS transistor T_(n31), leakage current detectionNchMOS transistor T_(n31) with a gate and drain in common and connectedto constant current source PchMOS transistor T_(p31), and a sourceconnected to low potential side supply voltage V_(ss), comparator COMP1comparing drain potential of leakage current detection NchMOS transistorT_(n31) and voltage amplified output potential V_(g1) due to currentmirror circuit 112, and PchMOS transistor T_(p11) with a sourceconnected to high potential side supply voltage V_(DD), a drainconnected to comparator COMP1, and control signal N from controller 121received at a gate via inverter circuit G5.

A substrate voltage control operation for semiconductor integratedcircuit apparatus 1300 of the configuration described above will bedescribed below.

The overall operation is the same as Embodiment 1 and descriptionthereof will be omitted. Only different aspects of the operation will bedescribed.

The configuration for the leakage current detection circuit is differentfrom Embodiment 1 shown in FIG. 1 in that a configuration is adoptedwhere the gate and drain of the leakage current detection NchMOStransistor T_(n31) are common and connected to constant current sourcePchMOS transistor T_(p31), and the source is connected to V_(SS). Inthis configuration, drain potential of leakage current detection NchMOStransistor T_(n31) is compared with V_(g1) that is a reference potentialusing a comparator. As a power supply voltage, V_(SS2) that is a voltagelower than V_(DD) and V_(SS) is applied to comparator COMP1. At internalcircuit 130, V_(SS) is connected to a plurality of NchMOS transistorsources. Output of comparator COMP1 is inputted to substrate voltagecontrol block 120.

Comparator COMP1 is comprised of a comparator and operational amplifier,and if the drain potential of leakage current detection. NchMOStransistor T_(n31) is higher than the reference potential of V_(g1),high level detection signal N is outputted. Substrate voltage controlblock 120 carries out the same operation as Embodiment 1 in that thesubstrate voltage is outputted, and the substrate voltage of leakagecurrent detection NchMOS transistor T_(n31) is raised (makes shallow).As a result, the threshold voltage of leakage current detection NchMOStransistor T_(n31) becomes small, and drain potential is lowered.Conversely, if the source potential is lower than the reference voltageV_(g1), comparator COMP1 outputs a low level detection signal N andsubstrate voltage control block 120 operates in such a manner as tolower (deepens) the substrate voltage of leakage current detectionNchMOS transistor T_(n31). As a result, the threshold voltage of leakagecurrent detection NchMOS transistor T_(n31) becomes large, and drainpotential is raised.

As in Embodiment 1, a circuit generating gate potential of leakagecurrent detection NchMOS transistor T_(n31) is comprised of referencevoltage generating circuit 111 and current mirror circuit 112. Therelationship between the detection ratio for the leakage current ofleakage current detection NchMOS transistor T_(n (LSI)) of the internalcircuit and the leakage current of the NchMOS transistor T_(n31) shownin equation (8) is also satisfied.

With the above circuit configuration, as it is possible to increase thedetection current value of leakage current detection NchMOS transistorT_(n31) by an arbitrary ratio, detect ion of leakage current, comparisonof the detected leakage current and target current value anddetermination of the result after comparison are extremelystraightforward.

Embodiment 14

Embodiment 14 is an example of applying a separate leakage currentdetection circuit to the leakage current detection circuit of theleakage current detection block.

FIG. 16 shows a configuration for a semiconductor integrated circuitapparatus of Embodiment 14 of the present invention. This embodimentshows an example applied to semiconductor integrated circuit apparatusequipped with a PchMOS transistor leakage current detection circuit,substrate voltage control block, and internal circuit. Componentsidentical to those in FIG. 3 are assigned the same numerals anddescription for the overlapped portions will be omitted.

In FIG. 16, semiconductor integrated circuit apparatus 1400 is equippedwith PchMOS transistor leakage current detection block 1410, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1400 adopts abasic configuration carrying out potential comparison of drain potentialof leakage current detection PchMOS transistor T_(p81) with a sourceconnected to V_(DD), the gate and drain connected together and connectedto a constant current source and a substrate voltage controlled bysubstrate voltage control block 120, for PchMOS transistor T_(p (LSI))equivalently representing internal circuit 130, and voltage amplifieroutput potential due to current mirror circuit 212 by a comparator.

Leakage current detection block 1410 is comprised of reference voltagegenerating circuit 211, current mirror circuit 212, and leakage currentdetection circuit 1413.

Leakage current detection circuit 1413 is comprised of constant currentsource NchMOS transistor T_(n81) with a source connected to lowpotential side supply voltage V_(ss) and a drain connected to leakagecurrent detection PchMOS transistor T_(p81), leakage current detectionPchMOS transistor T_(p81) with a gate and drain in common and connectedto constant current source NchMOS transistor T_(n81), and a sourceconnected to high potential side supply voltage V_(DD), comparator COMP2comparing drain potential of leakage current detection PchMOS transistorT_(p81) and voltage amplified output potential V_(g11) due to currentmirror circuit 212, and NchMOS transistor T_(n61) with a sourceconnected to low potential side supply voltage V_(ss), a drain connectedto comparator COMP2, and control signal P from controller 121 receivedat a gate via inverter circuit G54.

In this embodiment, the theory of operation is exactly the same as forthe circuit shown in FIG. 15 simply with NchMOS transistors changed forPchMOS transistors, and vice versa. Therefore, in this embodiment 14also and as in Embodiment 13, as it is possible to increase thedetection current value of leakage current detection PchMOS transistorT_(p81) by an arbitrary ratio, detection of leakage current, comparisonof the detected leakage current and target current value anddetermination of the result after comparison are extremelystraightforward.

Embodiment 13 and Embodiment 14 described above show an example appliedto a threshold voltage control circuit using a leakage current detectionMOS transistor with a gate and drain in common and a comparator. It ispossible to apply a configuration employing a leakage current detectionMOS transistor with a gate and drain in common and a comparator to aconfiguration that is a combination of voltage amplifying circuitsemploying operational amplifiers shown in Embodiment 3 and Embodiment 4of FIG. 4 and FIG. 5 and the reference voltage generating circuits shownin Embodiment 5 to Embodiment 8 of FIG. 6 to FIG. 9, and the sameeffects can be obtained.

Embodiment 15

Embodiment 15 is an example of applying a separate leakage currentdetection circuit to the leakage current detection circuit of theleakage current detection block.

FIG. 17 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 15 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 12 and FIG. 15 are assigned thesame numerals and description for the overlapped portions will beomitted.

In FIG. 17, semiconductor integrated circuit apparatus 1500 is equippedwith NchMOS transistor leakage current detection block 1510, substratevoltage control block 1120 controlling substrate voltage, and internalcircuit having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1500 adopts abasic configuration carrying out potential comparison of drain potentialof leakage current detection NchMOS transistor T_(n31) with a sourceconnected to V_(SS), and the gate and drain connected together andconnected to a constant current source and a substrate voltagecontrolled by substrate voltage control block 1120, for NchMOStransistor T_(n (LSI)) equivalently representing internal circuit 130,and voltage amplifier output potential due to current mirror circuit 112by a comparator.

Leakage current detection block 1510 is comprised of reference voltagegenerating circuit 111, current mirror circuit 112, and leakage currentdetection circuit 1513.

Leakage current detection circuit 1513 adopts a configuration whereinput switching switch 1114 for switching between drain potential ofleakage current detection NchMOS transistor T_(n31) and V_(g1) that is areference potential and respective input terminals IN1, IN2 ofcomparator COMP1 is further inserted at leakage current detectioncircuit 1513 of FIG. 15. The configuration of input switching switch1114 is the same as FIG. 13.

The circuit configuration and substrate voltage control operation ofsubstrate voltage control block 1120 is exactly the same as forEmbodiment 13 of FIG. 15, and a method for canceling DC offset ofcomparator COMP1 is exactly the same as for Embodiment 11.

Further, a circuit generating gate potential of leakage currentdetection NchMOS transistor T_(n31) is comprised of reference voltagegenerating circuit 111 and current mirror circuit 112. The relationshipbetween the detection ratio for the leakage current of the leakagecurrent detection NchMOS transistor T_(n (LSI)) of the internal circuitand the leakage current of the leakage current detection NchMOStransistor T_(n31) shown in equation (8) is also satisfied.

Therefore, in this embodiment also and as in Embodiment 13, as it ispossible to increase the detection current value of leakage currentdetection NchMOS transistor T_(n31) by an arbitrary ratio, detection ofleakage current, comparison of the detected leakage current and targetcurrent value and determination of the result after comparison areextremely straightforward. In addition to this effect, as withEmbodiment 11, it is possible to completely cancel the DC offset ofcomparator COMP1, and substantially improve the precision of controllingsubstrate voltage.

Embodiment 16

Embodiment 16 is an example applying a separate leakage currentdetection circuit to the leakage current detection circuit of theleakage current detect ion block.

FIG. 18 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 16 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with a PchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 14 and FIG. 16 are assigned thesame numerals and description for the overlapped portions will beomitted.

In FIG. 18, semiconductor integrated circuit apparatus 1600 is equippedwith PchMOS transistor leakage current detection block 1610, substratevoltage control block 1120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1600 adopts abasic configuration carrying out potential comparison of drain potentialof leakage current detection PchMOS transistor T_(p81) with a sourceconnected to V_(DD), the gate and drain connected together and connectedto a constant current source and a substrate voltage controlled bysubstrate voltage control block 1120, for PchMOS transistor T_(p (LSI))equivalently representing internal circuit 130, and voltage amplifieroutput potential due to current mirror circuit 212 by a comparator.

Leakage current detection block 1610 is comprised of reference voltagegenerating circuit 211, current mirror circuit 212, and leakage currentdetection circuit 1613.

Leakage current detection circuit 1613 adopts a configuration whereinput switching switch 1114 for switching between drain potential ofleakage current detection PchMOS transistor T_(p81) and V_(g11) that isa reference potential and respective input terminals IN1, IN2 ofcomparator COMP2 is further inserted at leakage current detectioncircuit 1413 of FIG. 16. The configuration of input switching switch1114 is the same as FIG. 13.

The circuit configuration and substrate voltage control operation ofsubstrate voltage control block 1120 is exactly the same as forEmbodiment 14 of FIG. 16, and a method for canceling DC offset ofcomparator COMP2 is exactly the same as for Embodiment 12.

In this embodiment, the theory of operation is exactly the same as forthe circuit shown in FIG. 17 simply with NchMOS transistors changed forPchMOS transistors, and vice versa. Therefore, in this embodiment 16also and as in Embodiment 14, as it is possible to increase thedetection current value of leakage current detection PchMOS transistorT_(p81) by an arbitrary ratio, and detection of leakage current,comparison of the detected leakage current and target current value anddetermination of the result after comparison are extremelystraightforward. In addition to this effect, as with Embodiment 12, itis possible to completely cancel the DC offset of comparator COMP2, andit is possible to substantially increase the precision of controllingsubstrate voltage.

Embodiment 15 and Embodiment 16 described above show an example appliedto a threshold voltage control circuit using a leakage current detectionMOS transistor with a gate and drain in common and a comparator. It ispossible to apply a configuration employing a leakage current detectionMOS transistor with a gate and drain in common and a comparator to aconfiguration that is a combination of voltage amplifying circuitsemploying operational amplifiers shown in Embodiment 3 and Embodiment 4of FIG. 4 and FIG. 5 and the reference voltage generating circuits shownin Embodiment 5 to Embodiment 8 of FIG. 6 to FIG. 9, and the sameeffects can be obtained.

Embodiment 17

Embodiment 17 is an example of varying current amplification ratio ofthe current mirror circuit.

FIG. 19 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 17 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 1 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 19, semiconductor integrated circuit apparatus 1700 is equippedwith NchMOS transistor leakage current detection block 1710, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1700 adopts abasic configuration employing leakage current detection NchMOStransistor T_(n1) with a drain connected to a constant current source,for leakage current detection of NchMOS transistor T_(n (LSI))equivalently representing internal circuit 130.

Leakage current detection block 1710 is comprised of current mirrorcircuit 1712, and leakage current detection circuit 113A. Leakagecurrent detection block 1710 arbitrarily amplifies a leakage currentvalue of leakage current detection NchMOS transistor T_(n1) of leakagecurrent detection circuit 113A using current mirror circuit 1712, andmakes detection of leakage current and determination straightforward.Further, it is possible to accelerate the response to substrate voltagecontrol so that fluctuation of substrate voltage can also be suppressed.Moreover, the configuration is such that current does not pass throughleakage current detection circuit 113A when leakage current detectioncircuit 113A is not operating.

Current mirror circuit 1712 adopts a configuration where NchMOStransistor T_(n13), and switch SW1 and switch SW2 are further added tocurrent mirror circuit 112 of FIG. 1.

Leakage current detection circuit 113A adopts a configuration wherePchMOS transistor T_(p101) and switch SW4 are added in parallel withPchMOS transistor T_(P1) of leakage current detection circuit 113 ofFIG. 1. In the above configuration, by putting switches SW1 and SW2 onand off, it is possible to change the ratio of channel width of NchMOStransistor T_(n4) and T_(n3) that are MOS transistors forming a pair forthe current mirror circuit and T_(n13), or it is possible to change thenumber of stages of the current mirror circuit and also to vary thecurrent amplification ratio. Further, the current value is adjustedaccording to the amplification ratio by switching switch SW4 accordingto the current amplification ratio of current mirror circuit 1712 andadjusting the current value of the constant current source constructedfrom PchMOS transistor T_(P101). For example, it is possible to make theNchMOS transistor appropriate for high speed operation by setting thecurrent amplification ratio to be small and the threshold voltage to below when power supply voltage is high. Conversely, it is possible tomake the NchMOS transistor appropriate for low power consumptionoperation by setting the current amplification ratio to be large and thethreshold voltage to be high when power supply voltage is low.

In the above, a substrate voltage control block of an NchMOS transistorhas been described, but it is also possible to apply the above similarlyto a threshold voltage control circuit constructed using PchMOStransistors, reference potential generating circuits of a separateconfiguration, or threshold voltage control circuits constructed usingleakage current detection circuits of a separate configuration.

Embodiment 18

Embodiment 18 is an example of varying voltage amplification ratio ofthe voltage amplifying circuit.

FIG. 20 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 18 of the present invention. Thisembodiment shows an example applied to semiconductor integrated circuitapparatus equipped with an NchMOS transistor leakage current detectioncircuit, substrate voltage control block, and internal circuit.Components identical to those in FIG. 4 are assigned the same numeralsand description for the overlapped portions will be omitted.

In FIG. 20, semiconductor integrated circuit apparatus 1800 is equippedwith NchMOS transistor leakage current detection block 1810, substratevoltage control block 120 controlling substrate voltage, and internalcircuit 130 having a plurality of MOS transistors on a semiconductorsubstrate. Semiconductor integrated circuit apparatus 1800 adopts abasic configuration employing leakage current detection NchMOStransistor T_(n1) with a drain connected to a constant current source,for leakage current detection of NchMOS transistor T_(n (LSI))equivalently representing internal circuit 130.

Leakage current detection block 1810 is comprised of reference voltagegenerating circuit 111, voltage amplifying circuit 1820, and leakagecurrent detection circuit 113A. Leakage current detection block 1810arbitrarily amplifies a leakage current value of leakage currentdetection NchMOS transistor T_(n1) of leakage current detection circuit113A using voltage amplifying circuit 1820, detects leakage current, andmakes detection of leakage current and determination straightforward.Further, it is possible to accelerate the response to substrate voltagecontrol so that fluctuation of substrate voltage can also be suppressed.Moreover, the configuration is such that current does not pass throughleakage current detection circuit 113A when leakage current detectioncircuit 113A is not operating.

Voltage amplifying circuit 1820 adopts a configuration where resistor R3and switch SW3 are further added in parallel to resistor R2 at voltageamplifying circuit 320 of FIG. 4. Leakage current detection circuit 113Aadopts a configuration where PchMOS transistor T_(p101) and switch SW4are added in parallel to PchMOS transistor T_(P1) of leakage currentdetection circuit 113 of FIG. 1.

By putting switch SW3 on and off and changing the ratio of the inputresistance value and output resistance value of voltage amplifyingcircuit 1820, it is possible to arbitrarily change the voltageamplification ratio according to power supply voltage. Further, thecurrent value is adjusted according to the amplification ratio byswitching switch SW4 according to the current amplification ratio ofvoltage amplifying circuit 1820 and adjusting the current value of theconstant current source constructed from PchMOS transistor T_(P101). Forexample, it is possible to make the NchMOS transistor appropriate forhigh speed operation by setting the voltage amplification ratio to besmall and the threshold voltage to be low when power supply voltage ishigh. Conversely, it is possible to make the NchMOS transistorappropriate for low power consumption operation by setting the voltageamplification ratio to be large and the threshold voltage to be highwhen power supply voltage is low.

In the above, a substrate voltage control block of an NchMOS transistorhas been described, but it is also possible to apply the above similarlyto a threshold voltage control circuit constructed using PchMOStransistors, reference potential generating circuits of a separateconfiguration, or threshold voltage control circuits constructed usingleakage current detection circuits of a separate configuration.

Embodiment 19

Embodiment 19 is an example of respectively controlling substratevoltage of PchMOS transistors and NchMOS transistors constituting a CMOScircuit at an internal circuit using both an NchMOS transistor thresholdvoltage control circuit and a PchMOS transistor threshold voltagecontrol circuit.

FIG. 21 shows a configuration for a semiconductor integrated circuitapparatus according to Embodiment 19 of the present invention.Components identical to those in FIG. 1 to FIG. 18 are assigned the samenumerals and description for the overlapped portions will be omitted.

In FIG. 21, semiconductor integrated circuit apparatus 1900 is equippedwith NchMOS transistor leakage current detection block 1910, substratevoltage control block 1920, PchMOS transistor leakage current detectionblock 2010, substrate voltage control block 2020, and internal circuit130. Semiconductor integrated circuit apparatus 1900 controls thethreshold voltage of the NchMOS transistor and PchMOS transistorconstituting internal circuit 130.

Leakage current detection blocks 1910 and 2010, and substrate voltagecontrol blocks 1920 and 2020 may operate with any combination of theleakage current detection blocks and substrate voltage control blocks ofeach of Embodiments 1 to 18.

In this way, according to this embodiment, the same effects are alsoobtained for CMOS circuits, and it is possible to improve detectionsensitivity and response of detection potential for a leakage currentdetection NchMOS transistor and a leakage current detection PchMOStransistor. Further, as a result of applying the above to an internalcircuit using CMOS circuits, it is possible to exert control bothsimultaneously and in an optimum manner on threshold voltages of thePchMOS transistors and NchMOS transistors.

Embodiment 20

FIG. 22 is a block view showing a configuration of electronic apparatushaving a threshold voltage control function according to Embodiment 20of the present invention.

In FIG. 22, electronic apparatus 3000 is equipped with power supplyapparatus 3100, and semiconductor integrated circuit apparatus 3200having a threshold voltage control function. Power supply apparatus 3100is comprised of power supply source 3110 composed of a battery and AC-DCconverter etc., power supply input terminals 3111 and 3112 inputting apower supply voltage generated by power supply source 3110, power supplyswitch 3120 switching the power supply voltage on and off, and voltagecontrol apparatus 3130 converting the power supply voltage of powersupply source 3110 to a voltage required by semiconductor integratedcircuit apparatus 3200 having a threshold voltage control function orgenerating and supplying this voltage.

Semiconductor integrated circuit apparatus 3200 is LSI apparatusreceiving supply voltages V_(DD), V_(SS), V_(DD2) and V_(SS2) fromvoltage control apparatus 3130 of power supply apparatus 3100.Semiconductor integrated circuit apparatus 3200 may be an individual oneor a combination of semiconductor integrated circuit apparatuses 100 to1900 described in each of Embodiments 1 to 19. Therefore, it is possibleto implement the superior effects of semiconductor integrated circuitapparatuses 100 to 1900 described in each of Embodiments 1 to 19, i.e.semiconductor integrated circuit apparatus 3200 having a leakage currentdetection circuit where an arbitrary set leakage current detection ratiodoes not depend on power supply voltage, temperature, or manufacturingvariations, detection of leakage current is straightforward, andresponse to substrate voltage control is fast. Further, by mountingsemiconductor integrated circuit apparatus 3200 on electronic apparatus3000, the effect of improving performance (in particular, powerconsumption) of electronic apparatus 3000 is fully expected.

Electronic apparatus 3000 using a battery as power supply source 3110 isextremely effective as portable equipment for use of long hours. It isalso expected that the effect of consuming less power will be sufficienteven for electronic apparatus employing an AC-DC converter as powersupply source 3110.

The preferred embodiments of the present invention described above aremerely given as examples, and they are not limited to the scope of thepresent invention.

Further, the title of “semiconductor integrated circuit apparatus andelectronic apparatus” is used in the forms of the embodiments, but thisis merely for simplicity of description. Therefore, the title may alsobe “threshold voltage control circuit apparatus,” “semiconductorintegrated circuit,” “mobile electronic equipment,” or “substratevoltage control method” etc.

Moreover, the type, number, and method of connecting each circuitsection constituting the semiconductor integrated circuit apparatus suchas, for example, comparators etc. are not limited to the embodimentsdescribed above.

The embodiments can be carried out for each of a plurality of circuitblocks the substrate may be electrically divided up into.

Further, it is possible to implement not only for MOS transistorsconfigured on a normal silicon substrate, but also for semiconductorintegrated circuits configured using MOS transistors of an SOI (SiliconOn Insulator) structure.

In the above, according to the present invention, it is possible toimplement semiconductor integrated circuit apparatus controllingthreshold voltage of MIS transistors having a leakage current detectioncircuit where arbitrarily set leakage current detection does not dependon power supply voltage, temperature or manufacturing variations, andwhere detection is straightforward, and response to substrate voltagecontrol is fast.

Further, it is possible to implement low power consumption of theleakage current detection circuit. Moreover, it is possible toarbitrarily set threshold voltage to an arbitrary system clock frequencyor power supply voltage.

The semiconductor integrated circuit apparatus and electronic apparatuscontrolling threshold voltage of transistors of the present invention istherefore capable of increasing the detection current value of leakagecurrent detection MOS transistors so that detection of leakage current,comparison of the detected leakage current and target current value anddetermination of the result after comparison are extremelystraightforward. Further, it is possible to accelerate the response tosubstrate voltage control so that fluctuation of substrate voltage canalso be suppressed. Further, it is possible for a constant currentsupply to take up a small surface area by setting current of a constantcurrent source connected to an MOS transistor to be large. It is thenpossible to keep the power consumed when leakage current detectioncircuit is not operating low by inserting an MOS transistor switchcontrolled by a control signal at a circuit constituting a constantcurrent source of the leakage current detection circuit. This istherefore extremely effective not only as a way of controlling variationof threshold voltages of semiconductor integrated circuits andelectronic apparatus operating at low power supply voltages, but also asa way of arbitrarily changing threshold voltage according to a changingpower supply voltage.

The present invention is not limited to the above described embodiments,and various variations and modifications may be possible withoutdeparting from the scope of the present invention.

This application is based on Japanese Patent Applications No.2005-299209 filed on Oct. 13, 2005, and No. 2006-175899 filed on Jun.26, 2006, entire content of which is expressly incorporated by referenceherein.

1. A semiconductor integrated circuit apparatus, comprising: a firstfirst main conductivity MIS transistor with a source connected to afirst power supply; a second first main conductivity MIS transistor witha source connected to a drain of the first first main conductivity MIStransistor, a drain connected to a first current source, and a gateconnected to a gate of the first first main conductivity MIS transistorand the first current source; a current mirror circuit that has a thirdfirst main conductivity MIS transistor with a source connected to thefirst power supply and that takes a drain potential of the first firstmain conductivity MIS transistor as a gate potential, and amplifies orattenuates a drain current of the third first main conductivity MIStransistor to a current value of an arbitrary ratio α; and a leakagecurrent detection first main conductivity MIS transistor that takes anoutput potential of the current mirror circuit as a gate potential, andhas a substrate connected to a substrate of a first main conductivityMIS transistor of an internal circuit, wherein: the current mirrorcircuit satisfies the following equation when the drain current of thethird first main conductivity MIS transistor is amplified α times,$\frac{I_{L.{LSI}}}{I_{L.{LCM}}} = {\frac{W_{LSI}}{L_{LCM}} \cdot \frac{W_{1}}{W_{2}} \cdot \frac{1}{\alpha}}$where: I_(L.LSI) is a leakage current of the first main conductivity MIStransistor of the internal circuit; I_(L.LCM) is a leakage current ofthe leakage current detection first main conductivity MIS transistor;W_(LSI) is a channel width of the first main conductivity MIS transistorof the internal circuit; W_(LCM) is a channel width of the leakagecurrent detection first main conductivity MIS transistor; W₁ is achannel width of the first first main conductivity MIS transistor; W₂ isa channel width of the second first main conductivity MIS transistor;and the first and second first main conductivity MIS transistors operatein a sub-threshold region in such a manner that an absolute value of adifference between a gate potential of the first first main conductivityMIS transistor and the second first main conductivity MIS transistor,and a potential of the first power supply, becomes equal to or smallerthan a threshold voltage of the first and second first main conductivityMIS transistors.
 2. A semiconductor integrated circuit apparatus,comprising: a first first main conductivity MIS transistor with a sourceconnected to a first power supply; a second first main conductivity MIStransistor with a source connected to a drain of the first first mainconductivity MIS transistor, and a drain connected to a first currentsource; a third first main conductivity MIS transistor with a sourceconnected to the first power supply, a gate and drain connected incommon to respective gates of the first first main conductivity MIStransistor and the second first main conductivity MIS transistor, and asecond current source; and a current mirror circuit that amplifies orattenuates a third first main conductivity MIS transistor with a sourceconnected to the first power supply and that takes a drain potential ofthe first first main conductivity MIS transistor as a gate potential toa current value of an arbitrary ratio, wherein the first, second andthird first main conductivity MIS transistors operate in a sub-thresholdregion in such a manner that an absolute value of a difference between agate potential of the first first main conductivity MIS transistor, thesecond first main conductivity MIS transistor and the third first mainconductivity MIS transistor, and a potential of the first power supply,becomes equal to or smaller than a threshold voltage of the first,second and third first main conductivity MIS transistors.
 3. Asemiconductor integrated circuit apparatus, comprising: an internalcircuit having a plurality of MIS transistors on a semiconductorsubstrate; a substrate voltage controller that supplies a substratevoltage to the internal circuit and controls a threshold voltage for theMIS transistors of the internal circuit; a reference potentialgenerating circuit; a current mirror circuit that amplifies orattenuates a drain current of an MIS transistor taking an outputpotential of the reference potential generating circuit as a gatepotential to a current value of an arbitrary ratio; and a leakagecurrent detection circuit including an MIS transistor with the substratevoltage supplied by the substrate voltage controller, and that takes anoutput potential of the current mirror circuit as a gate potential,wherein: a threshold voltage is controlled by inputting an output signalof the leakage current detection circuit to the substrate voltagecontroller; the internal circuit has a complementary metal insulatedsemiconductor (CMIS) circuit; the semiconductor integrated circuitapparatus provides a substrate voltage controller, a reference potentialgenerating circuit, a current mirror circuit, and a leakage currentdetection Nch MIS transistor, to control a threshold voltage for Nch MIStransistors of the internal circuit; and the semiconductor integratedcircuit apparatus sets a substrate voltage controller, a referencepotential generating circuit, a current mirror circuit, and a leakagecurrent detection Pch MIS transistor, to control a threshold voltage forPch MIS transistors of the internal circuit.